Ci a ion: Ma ini, A.D.; Dalleck, L.C.;
Meju o, G.; La wood, T.; Wea he wax,
R.M.; Ramos, J.S. Changes in he
Second Ven ila o y Th eshold
Following Indi idualised e sus
S anda dised Exe cise P esc ip ion
among Physically Inac i e Adul s: A
Randomised T ial. In . J. En i on. Res.
Public Heal h 2022,19, 3962. h ps://
doi.o g/10.3390/ije ph19073962
Academic Edi o s: Paul B.
Tchounwou and Ge mán
Vicen e-Rod íguez
Recei ed: 6 Feb ua y 2022
Accep ed: 23 Ma ch 2022
Published: 26 Ma ch 2022
Publishe ’s No e: MDPI s ays neu al
wi h ega d o ju isdic ional claims in
published maps and ins i u ional a il-
ia ions.
Copy igh : © 2022 by he au ho s.
Licensee MDPI, Basel, Swi ze land.
This a icle is an open access a icle
dis ibu ed unde he e ms and
condi ions o he C ea i e Commons
A ibu ion (CC BY) license (h ps://
c ea i ecommons.o g/licenses/by/
4.0/).
In e na ional Jou nal o
En i onmen al Resea ch
and Public Heal h
A icle
Changes in he Second Ven ila o y Th eshold Following
Indi idualised e sus S anda dised Exe cise P esc ip ion
among Physically Inac i e Adul s: A Randomised T ial
Alex D. Ma ini 1, Lance C. Dalleck 1,2 , Gaizka Meju o 3, T en La wood 1, Ryan M. Wea he wax 4
and Joyce S. Ramos 1,*
1SHAPE Resea ch Cen e, Ca ing Fu u es Ins i u e, Clinical Exe cise Physiology, College o Nu sing and
Heal h Sciences, Flinde s Uni e si y, Adelaide, SA 5042, Aus alia; [email p o ec ed] (A.D.M.);
[email p o ec ed] (L.C.D.); [email p o ec ed] (T.L.)
2
Rec ea ion, Exe cise, and Spo Science Depa men , Wes e n Colo ado Uni e si y, Gunnison, CO 81231, USA
3Facul y o Educa ion, Uni e si y o he Basque Coun y, 48940 Leioa, Spain; [email p o ec ed]
4Heal h and Kinesiology Depa men , Uni e si y o U ah, Sal Lake Ci y, UT 84112, USA;
[email p o ec ed]
*Co espondence: [email p o ec ed]
Abs ac :
The second en ila o y h eshold (VT
2
) is es ablished as an impo an indica o o exe cise
in ensi y ole ance. A highe VT
2
allows o g ea e du a ion o highe in ensi y exe cise pa icipa ion
and subsequen ly g ea e educ ions in ca dio ascula disease (CVD) isk. This s udy aimed o com-
pa e he e icacy o s anda dised and indi idualised exe cise p esc ip ion on VT
2
among physically
inac i e adul s. Fo y-nine physically inac i e male and emale pa icipan s (48.6
±
11.5 yea s) we e
ec ui ed and andomised in o a 12-week s anda dised (n= 25) o indi idualised (n= 24) exe cise
p esc ip ion in e en ion. The exe cise in ensi y o he s anda dised and indi idualised g oups was
p esc ibed as a pe cen age o hea a e ese e (HRR) o ela i e o he i s en ila o y h eshold
(VT
1
) and VT
2
, espec i ely. Pa icipan s we e equi ed o comple e a maximal g aded exe cise es a
p e-and pos -in e en ion o de e mine VT
1
and VT
2
. Pa icipan s we e ca ego ised as esponde s o
he in e en ion i an absolu e VT
2
change o a leas 1.9% was a ained. Thi y-eigh pa icipan s we e
included in he analysis. A signi ican di e ence in VT
2
change was ound be ween indi idualised
(p e s. pos : 70.6% s. 78.7% maximum oxygen up ake (VO
2
max)) and s anda dised (p e s. pos :
72.5% s. 72.3% VO
2
max) exe cise g oups. Indi idualised exe cise p esc ip ion was signi ican ly
mo e e icacious (p= 0.04) in elici ing a posi i e esponse in VT
2
(15/19, 79%) when compa ed o
he s anda dised exe cise g oup (9/19, 47%). Indi idualised exe cise p esc ip ion appea s o be
mo e e icacious han s anda dised exe cise p esc ip ion in elici ing a posi i e VT
2
change among
physically inac i e adul s. Inc easing VT
2
allows o g ea e ole ance o highe exe cise in ensi ies
and he e o e g ea e ca dio ascula heal h ou comes.
Keywo ds:
en ila o y h eshold; indi idualised exe cise p esc ip ion; s anda dised exe cise
p esc ip ion; ca dio ascula disease; ca dio ascula heal h; physically inac i e
1. In oduc ion
Ex ensi e esea ch has p esen ed he enhanced heal h bene i s o pe o ming highe
in ensi ies o exe cise [
1
]. High-in ensi y exe cise pa icipa ion has been demons a ed
o p omo e g ea e ca dio ascula heal h bene i s when compa ed o low in ensi y exe -
cise [
2
,
3
]. Indeed, exe cise in ensi y has been es ablished as he single mos impo an
aspec o ae obic exe cise p esc ip ion in educing ca dio ascula dea h isk and all-cause
mo ali y [
4
]. Weekly pa icipa ion in a single bou o high-in ensi y exe cise has been
ecognised o signi ican ly educe ca dio ascula disease isk [
4
]. No addi ional bene i
was ound in inc easing he du a ion o numbe o sessions pe week [
4
]. Fu he mo e,
In . J. En i on. Res. Public Heal h 2022,19, 3962. h ps://doi.o g/10.3390/ije ph19073962 h ps://www.mdpi.com/jou nal/ije ph
In . J. En i on. Res. Public Heal h 2022,19, 3962 2 o 13
high-in ensi y exe cise is ecognised o be mo e e ec i e, when compa ed o lowe exe cise
in ensi ies, a educing me abolic synd ome (Me S) disease isk, a condi ion associa ed wi h
a 60% inc ease in ca dio ascula disease (CVD) isk [
5
]. P e ious li e a u e es ablished
he isk o de eloping Me S could be dec eased by 3–10% h ough egula pa icipa ion
in mode a e o igo ous physical ac i i y [
6
]. No signi ican educ ion in Me S isk was
ecognised among hose who pa icipa ed in ligh physical ac i i y [
6
]. Ul ima ely, such
p o ound impac high-in ensi y exe cise has on educing o e all CVD isk is hough o
be a esul o i s supe io i y in imp o ing ca dio espi a o y i ness (CRF), as measu ed by
peak o maximum VO
2
(VO
2
peak o VO
2
max) [
7
–
9
]. Well-documen ed esea ch highligh s
high-in ensi y exe cise as being he mos e ec i e aining me hod in imp o ing CRF when
compa ed o al e na e exe cise in ensi ies [
7
–
9
]. Inc eased exe cise pa icipa ion a igo ous
o high in ensi ies has also been associa ed wi h g ea e imp o emen s in glucose u iliza ion,
as well as signi ican imp o emen s in insulin s imula ed supp ession o adipose issue
lipolysis [
10
]. Ul ima ely, a high second en ila o y h eshold (VT
2
) allows o a g ea e
capaci y o pe o m highe exe cise in ensi ies, and he e o e be e heal h ou comes.
The VT
2
is ecognised as he poin du ing inc emen al exe cise a which an exponen ial
inc ease in minu e en ila ion (V
E
) ela i e o VO
2
(oxygen up ake) occu s [
11
]. The s eep
climb in V
E
, a p oduc o espi a o y a e and idal olume, is d i en by he heigh ened
ca bon dioxide (CO
2
) p oduc ion as a consequence o hyd ogen ion accumula ion as
exe cise in ensi y p og esses [
12
]. VT
2
signi ies he poin be ween easily sus ained exe cise
and exe cise ha is only able o be sus ained o a sho pe iod o ime. Ul ima ely, VT
2
has been es ablished as an impo an indica o o o e all exe cise ole ance [
1
,
12
–
14
].
Speci ically, i is ecognised as a good ma ke o one’s abili y o pe o m highe in ensi ies
o exe cise o longe du a ions [13].
I is well ecognized ha exe cising a a high in ensi y leads o g ea e imp o emen s
in VT
2
[
15
]. Commonly, wo o ms o exe cise in ensi y p esc ip ion a e used among a h-
le ic and clinical popula ions, namely, s anda dised and indi idualised [
16
]. S anda dised
exe cise p esc ip ion p esen s as he mos common o m and is ecognised as p esc ibing
exe cise based on a ela i e pe cen age o a physiological pa ame e such as hea a e
(i.e., pe cen age o hea a e ese e [HRR] o hea a e maximum) [
16
]. Compa a i ely,
indi idualised exe cise p esc ip ion is de i ed om indi idual physiological h esholds
such as VT
2
and VT
1
( he i s en ila o y h eshold) [
17
]. VT1 is de ined as he ini ial
inc ease in VE du ing inc emen al exe cise, indica ing he bounda y be ween low- o
mode a e-in ensi y exe cise [
12
]. Indeed, indi idualised exe cise p esc ip ion has been
sugges ed o be mo e e ec i e in elici ing an o e all posi i e aining esponse in compa i-
son o s anda dised exe cise p esc ip ion. Speci ically, Wolpe n e al. [
17
] p esen ed ha
100% o appa en ly heal hy seden a y pa icipan s p esc ibed wi h indi idualised exe cise
demons a ed a s a is ically signi ican inc ease in o e all ela i e VO
2
max in con as o
only 41.7% o hose p esc ibed wi h s anda dised exe cise p esc ip ion. Howe e , o he
au ho s knowledge, esea ch hus a has ye o di ec ly in es iga e he e ec s o change
in VT
2
measu es ollowing indi idualised and s anda dised exe cise p esc ip ion among
physically inac i e adul s.
The aim o his s udy was o compa e wo app oaches o ae obic exe cise in ensi y
p esc ip ion (s anda dised e sus indi idualised) on VT
2
among physically inac i e adul s
o e a 12-week exe cise in e en ion. I was hypo hesised ha indi idualised exe cise
p esc ip ion would be mo e e ec i e in inc easing VT
2
compa ed o s anda dised exe cise
p esc ip ion in physically inac i e adul s.
2. Ma e ials and Me hods
2.1. Resea ch Design and Me hodology
The s udy ec ui ed physically inac i e males and emales in e es ed in imp o ing
hei o e all heal h and wellness. The p esen s udy is a sub-s udy o a p e iously pub-
lished in es iga ion [
18
], epo ing on VT
2
as a p ima y ou come. Only hose who had a
leas 70% adhe ence o he exe cise in e en ions we e included in he analysis o his sub-
In . J. En i on. Res. Public Heal h 2022,19, 3962 3 o 13
s udy. Pa icipan s we e ec ui ed om a communi y wellness p og am ia ad e isemen
a he local uni e si y and newspape . To mee he inclusion c i e ia o he in es iga ion,
pa icipan s we e equi ed o be cu en ly comple ing less han 30 min o physical ac i i y
on h ee days a week o less and be aged be ween 30–75 yea s. Pa icipan s comple ed he
In e na ional Physical Ac i i y Ques ionnai e (IPAQ) o iden i y physical ac i i y le els
and con i m s udy eligibili y [
19
]. Pa icipan s we e allowed o cla i y any ques ions o
ensu e co ec inclusion c i e ia was me . In o de o ensu e pa icipan sa e y, indi iduals
we e equi ed o unde go a s anda d medical his o y ques ionnai e and an in ake in e iew.
Pa icipan s who iden i ied signs o symp oms consis en wi h pulmona y, ca dio ascu-
la o me abolic condi ions wi hin he sc eening we e excluded om he in es iga ion.
Pa icipan s we e also equi ed o e bally con i m ha hey would no al e hei egu-
la nu i ional in ake habi s h oughou he in e en ion. To moni o nu i ional in ake,
pa icipan s we e ins uc ed o comple e a nu i ional logbook, de ailing hei nu i ional
in ake in he p e ious h ee days. This occu ed a p e-and pos -exe cise in e en ion
es ing. Nu i ional in o ma ion sou ced wi hin he 3-day die a y logs ( wo weekdays
and one weekend day) included he ype and quan i y o ood consumed, b and o ood,
how i was p epa ed and he ime o day o consump ion. This allowed he mos accu a e
ene gy in ake, pe cen age o mac onu ien s and g ams o mic onu ien s consumed o
be analysed. W i en in o med consen was ob ained om all s udy pa icipan s p io o
ini ia ion o he s udy. A ull desc ip ion o he andomized con ol ial me hodology and
a ionale has been p e iously published in de ail [
20
]. The s udy e hics we e app o ed
by he Auckland Uni e si y o Technology E hics Commi ee (16/264) and Wes e n S a e
Colo ado Uni e si y Ins i u ional Re iew Boa d (HRC2016-01-90R6).
Expe imen al es ing was conduc ed a baseline and pos 12-week exe cise in e en ion.
In o de o dec ease da a a iabili y, p e- and pos -exe cise expe imen al es ing was
comple ed on he same ime and day o he week. Pa icipan s we e ins uc ed o a oid
consump ion o ood and s enuous exe ion o 12 h p io o es ing. The pos expe imen al
assessmen ook place 2–3 days ollowing he las exe cise aining session.
2.2. Ven ila o y Th eshold
Upon a i al a he labo a o y and 20–30 min p io o comple ing a g aded exe cise
es (GXT), basic an h opome ic and es ing HR alues we e assessed. Res ing HR was
assessed ollowing i e minu es o sea ed es wi h back suppo , ee on he g ound, and
a ms suppo ed nea hea le el in a dis ac ion ee assessmen oom. A e he 5 min o
es , a medical-g ade pulse oxime e (Nonin Medical Inc., Plymou h, MN, USA) was used
o es ablish a es ing HR measu e. Subsequen ly, pa icipan s we e weighed o he nea es
0.1 kg on a medical g ade scale and heigh was measu ed o he nea es 0.5 cm using a
s adiome e (Tani a Co po a ion WB-3000, Tokyo, Japan).
To de e mine VT
2
, a g aded exe cise es (GXT) o exhaus ion was conduc ed h ough
implemen a ion o a modi ied Balke pseudo- amp p o ocol on a mo o ized eadmill (Pow-
e jog GX200, Po land, ME, USA). A 4 min wa m-up was conduc ed o each pa icipan a
a sel -selec ed speed and incline o 0%. Following wa m-up, he eadmill incline was in-
c eased by 1% e e y minu e un il exhaus ion. To moni o hea a e (HR), a ches s ap and
adio eleme ic de ice (Pola Elec o, Woodbu y, NT, USA) was used. Expi ed oxygen (O
2
)
and CO
2
exchange da a we e analysed using a me abolic analyse (Pa o Medics T ueOne
2.0, Sal Lake Ci y, UT, USA). The me abolic analyse was calib a ed agains a known gas
mix u e (16% O
2
and 4% CO
2
) and oom ai (20.93% O
2
and 0.03% CO
2
), as ou lined in he
manu ac u e ’s ins uc ion manual. The inal wo highes 15 s epochs we e a e aged o
ep esen he pa icipan s’ VO
2
max. To asce ain ha he pa icipan comple ed a maximal
exe cise es , a e i ica ion p o ocol was implemen ed. This e i ica ion p ocedu e has
been es ablished as a obus and accu a e measu e o indica e i pa icipan s ha e indeed
achie ed a VO
2
max alue [
21
]. Such p o ocol in ol ed ins uc ing he pa icipan s o
comple e a ou -minu e wa m-up, 20 min a e he comple ion o he GXT, ollowed by
a oli ional es o exhaus ion a a cons an wo kload ha was 5% highe han he las
In . J. En i on. Res. Public Heal h 2022,19, 3962 4 o 13
comple ed s age o he GXT. The cons an wo kload used o he e i ica ion p ocedu e
was de e mined by inc easing he speed, incline, o combina ion o hese o achie e a 5%
highe MET alue han he maximal MET alue achie ed du ing he GXT. Pa icipan s
we e encou aged o comple e a du a ion g ea e han wo minu es. The VO
2
max achie ed
du ing he e i ica ion p o ocol was also calcula ed by aking he a e age o he highes
15 s epochs. A maximal exe cise es was con i med i he wo maximal VO
2
alues we e
wi hin 3% o each o he , since his is ecognised as he measu emen e o o he me abolic
analyse . I he disc epancy was g ea e han 3%, he pa icipan s we e asked o epea he
GXT and e i ica ion p o ocol 24–72 h ollowing un il con i ma ion o a maximal exe cise
es was achie ed [
22
]. The highes measu ed HR du ing he GXT was ecognised o be he
pa icipan s maximal HR. Hea a e ese e (HRR) was hen calcula ed by sub ac ing he
di e ence o HRmax ob ained du ing he maximal GXT and es ing HR assessed
20–30 min
p io o GXT, as desc ibed p e iously.
The i s en ila o y h eshold (VT
1
) was necessa y o iden i y o guide exe cise p e-
sc ip ion among he indi idualised g oup. This measu e deno es he poin be ween ligh o
mode a e exe cise in ensi y and was iden i ied as he poin a which VE/VO
2
inc eased
wi h no subsequen inc ease in VE/VCO
2
as de e mined by he me abolic analyse (Pa o
Medics T ueOne 2.0, Sal Lake Ci y, UT, USA). VT
2
was iden i ied as he poin whe e
VE/VO
2
and VE/VCO
2
simul aneously inc eased, de e mined by he me abolic analyse
so wa e (Pa o Medics T ueOne 2.0, Sal Lake Ci y, UT, USA). This VT analysis echnique
has been used in nume ous simila s udies [
15
,
23
,
24
]. VT
2
was exp essed as a pe cen age
o absolu e VO2max.
2.3. Exe cise P esc ip ion
Pa icipan s we e andomised in o ei he s anda dised exe cise p esc ip ion o indi id-
ualised exe cise p esc ip ion (Figu e 1). This was achie ed by using a compu e -gene a ed
sequence o andom numbe s s a i ied by sex. Following andomisa ion in o one o he
wo exe cise in e en ions pa icipan s exe cised h ee imes a week o 12 weeks.
Exe cise wo kload o he s anda dised exe cise g oup was p esc ibed acco ding o
he Ame ican College o Spo s Medicine (ACSM) guideline [
16
], as a a ge hea a e (HR)
ange calcula ed as pe cen age o HRR using he ollowing equa ion:
Ta ge HR ange =[(MaximalHR −Res ingHR)∗Desi ed%HR]+Res ingHR (1)
Exe cise in ensi y wi hin he indi idualised exe cise g oup was calcula ed based o
HR anges ela i e o VT
1
and VT
2
calcula ed du ing he GXT. Pa icipan s wi hin he
indi idualised exe cise g oup had hei exe cise in ensi y zones es ablished h ough he
ollowing equa ions acco ding o he Ame ican Council on Exe cise (ACE) guidelines [
17
]:
•
Ta ge HR < VT
1
= HR ange: 10 bea s pe minu e (bpm) below VT
1
o he HR a VT
1
•Ta ge HR ≥VT1 o < VT2= HR ange: 15 bpm abo e VT1 o below VT2
•Ta ge HR ≥VT2= HR ange: Hea a e a VT2 o 10 bpm abo e VT2
Figu e 1ou lines he p og ession in o e all exe cise in ensi y o he exe cise in e en-
ion g oups. Exe cise olume o bo h g oups was calcula ed based on ene gy expendi u e
pe kg o body weigh pe week (kcal
·
kg
−1·
wk
−1
) o ensu e exe cise olume was ma ched
be ween bo h in e en ions. The ene gy expendi u e was de e mined by associa ing he
exe cise HR p esc ibed wi h he ene gy expendi u e de i ed om he maximal GXT. Body
weigh (kg) was measu ed ia medical g ade scales o he nea es 0.1 kg.
In . J. En i on. Res. Public Heal h 2022,19, 3962 5 o 13
In . J. En i on. Res. Public Heal h 2022, 19, x 5 o 13
Figu e 1. Exe cise p esc ip ion p og ession among bo h iso-calo ic exe cise in e en ion g oups
h oughou he in e en ion. HRR: Hea Ra e Rese e; HR: Hea a e; VT
1
: Ven ila o y h eshold
1; VT
2
: Ven ila o y h eshold 2; Kcal: kilocalo ies.
2.4. Exe cise T aining
Figu e 1.
Exe cise p esc ip ion p og ession among bo h iso-calo ic exe cise in e en ion g oups
h oughou he in e en ion. HRR: Hea Ra e Rese e; HR: Hea a e; VT
1
: Ven ila o y h eshold 1;
VT2: Ven ila o y h eshold 2; Kcal: kilocalo ies.
In . J. En i on. Res. Public Heal h 2022,19, 3962 6 o 13
2.4. Exe cise T aining
Upon a i al o he p esc ibed exe cise sessions, pa icipan s we e ins uc ed o es
in a sea ed posi ion o i e minu es. A e i e minu es o sea ed es , es ing HR and
blood p essu e we e measu ed and eco ded o ensu e i was sa e o he pa icipan s
o pe o m exe cise and used o moni o eco e y ollowing cessa ion o he exe cise
session. Blood p essu e was measu ed on he pa icipan s le a m using a s e hoscope and
sphygmomanome e (Ame ican Diagnos ic Co po a ion Diagnos ic 700 Se ies, Hauppauge,
NY, USA). Depending on p e e ence and a ailabili y, pa icipan s comple ed exe cise
sessions on ei he a mo o ised eadmill, ellip ical aining and/o a s a iona y bike. In
o de o limi luc ua ions in acu e exe cise in ensi ies compa ed o p esc ibed in ensi y,
pa icipan s we e limi ed o 5 and 10 min o use o he s a iona y bike and ellip ical
aine , espec i ely, wi h he majo i y o he exe cise occu ing wi h he use o a mo o ized
eadmill. This a ie y in modali y was implemen ed o inc ease enjoymen and mimic
a communi y wellness p og am se ing. Pa icipan s we e ins uc ed o wa m-up a a
sel -selec ed pace and wo kload o i e minu es, a which poin he p esc ibed exe cise
in ensi y was eached and he pa icipan el eady o begin. The pa icipan s wo ked a
such in ensi y o he calcula ed exe cise du a ion, based on alues ob ained du ing he GXT
wi h con inuous moni o ing (1/3 and 2/3 o he o al ime o exe cise) o HR h ough use o
a ches s ap and adio eleme y ecei e (Pola Elec o, Woodbu y, NY, USA). This me hod
helped ensu e he co ec p esc ibed exe cise in ensi y was being used h oughou he
session. Following he wo kload pe iod, pa icipan s pe o med a i e-minu e cool-down
wi h dec easing wo kload un il HR e u ned o wi hin 15 bpm o es ing HR.
2.5. Da a Managemen and Analysis
Da a analysis was comple ed using SPSS e sion 25.0. Assump ion o no mali y was
con i med h ough use o he Shapi o–Wilk es s. Analysis o VT
2
change was based on
indi idual esponses and compa ed o a de e mined h eshold o a clinically meaning ul
change. The h eshold o indi idual change o VT
2
was assessed based on a simila
me hodology in es iga ing six concep s o lac a e h eshold (a simila measu e o VT
2
) o
calcula e he subjec coe icien o a ia ion, ecognised as 1.9% [
25
]. Such alue could
ca ego ise each pa icipan as ei he a likely esponde o likely non- esponde . Pa icipan s
who demons a ed a VT
2
change o
≥
1.9%, deemed o indica e a meaning ul change,
we e ca ego ised as likely esponde s, while hose who demons a ed a change o <1.9%
we e ca ego ized as likely non- esponde s wi h no clinically meaning ul change in VT
2
.
A epea ed measu es ANCOVA was used o analyse he be ween-g oup di e ences o
change in VT
2
and o he con inuous physiological a iables collec ed om baseline o pos
in e en ion. Baseline alues we e assigned as he co a ia e, while he dependen a iable
was ecognised as he pos -exe cise in e en ion alues. The Chi-squa e es was used o
analyse he p opo ion o esponde s o a clinically meaning ul change in VT
2
be ween
g oups. S a is ical signi icance was se a p< 0.05.
3. Resul s
O he 49 pa icipan s ec ui ed, a o al o 11 wi hd ew o we e no included in he
analysis. This was due o un ela ed medical issues (n= 3), alling below 70% adhe ence
(
n= 4
), sel -wi hd awal (n= 3), and incomple e p e- and pos -in e en ion VT
2
da a (n= 1)
(Figu e 2). Consequen ly, 38 pa icipan s we e included wi hin he inal da a analyses. The
s anda dised exe cise in e en ion g oup eco ded a mean adhe ence ac oss he 12 weeks
o 82.9%
±
5.7%, while he indi idualised exe cise in e en ion g oup eco ded a mean
adhe ence o 86.1% ±4.7%.
In . J. En i on. Res. Public Heal h 2022,19, 3962 7 o 13
In . J. En i on. Res. Public Heal h 2022, 19, x 7 o 13
Figu e 2. Numbe o pa icipan s ec ui ed and a ionale o da a analysis exclusion.
Mean p e-and pos -exe cise in e en ion pa ame e cha ac e is ics a e p esen ed in
Table 1. A signi ican be ween g oup di e ence in VO2max was no ed a baseline. The
indi idualised exe cise g oup eco ded a mean absolu e VO2max o 2.0 ± 0.6 (L·min),
while he s anda dised exe cise g oup eco ded a mean o 2.4 ± 0.8 (L·𝑚𝑖𝑛). The e was
no signi ican change in mean calo ic in ake om p e- o pos -exe cise in e en ion be-
ween g oups (p > 0.05).
Table 1. P e- and pos -mean ou come measu es o s anda dised and indi idualised exe cise
g oups.
Pa ame e s
S anda dised
(n = 19; Women, n = 15; Men, n = 4)
Indi idualised
(n = 19; Women, n = 14; Men, n = 5) Be ween-G oup Di e ence
P e Pos P e Pos p-Value
Age 52.3 ± 11.7 - 45.0 ± 11.3 - -
Heigh 168.3 ± 9.6 - 172.2 ± 7.0 - -
Weigh 84.7 ± 21.1 84.2 ± 20.2 80.2 ± 15.5 80.3 ± 15.6 -
VT2 (% VO2max) 72.5 ± 7.8 72.3 ± 5.5 70.6 ± 8.5 78.7 ± 6.0 * <0.001
Absolu e VO2 a VT2
(L/min) 1.5 ± 0.5 1.6 ± 0.5 1.7 ± 0.5 2.0 ± 0.7 * 0.017
Rela i e VO2 a VT2
(mL/kg/min) 17.3 ± 3.5 18.7 ± 3.1 20.8 ± 5.3 24.7 ± 7.1 * 0.016
VO2max (L/min) 2.0 ± 0.6 2.2 ± 0.6 2.38 ± 0.8 2.5 ± 0.8 0.579
VO2max
(mL/kg/min) 24.0 ± 4.7 25.9 ± 4.8 29.7 ± 7.8 31.4 ± 8.5 0.635
Daily calo ic in ake (kcal) 1519 ± 563 1518 ± 500 1539 ± 493 1555 ± 403 0.967
* S a is ically signi ican (p < 0.05) di e ence a pos -in e en ion be ween g oups.
Figu e 2. Numbe o pa icipan s ec ui ed and a ionale o da a analysis exclusion.
Mean p e-and pos -exe cise in e en ion pa ame e cha ac e is ics a e p esen ed in
Table 1. A signi ican be ween g oup di e ence in VO
2
max was no ed a baseline. The
indi idualised exe cise g oup eco ded a mean absolu e VO
2
max o 2.0
±
0.6 (L
·min−1
),
while he s anda dised exe cise g oup eco ded a mean o 2.4
±
0.8 (L
·min−1
). The e was
no signi ican change in mean calo ic in ake om p e- o pos -exe cise in e en ion be ween
g oups (p> 0.05).
Table 1.
P e- and pos -mean ou come measu es o s anda dised and indi idualised exe cise g oups.
Pa ame e s
S anda dised
(n= 19; Women, n= 15; Men, n= 4)
Indi idualised
(n= 19; Women, n= 14; Men, n= 5)
Be ween-G oup
Di e ence
P e Pos P e Pos p-Value
Age 52.3 ±11.7 - 45.0 ±11.3 - -
Heigh 168.3 ±9.6 - 172.2 ±7.0 - -
Weigh 84.7 ±21.1 84.2 ±20.2 80.2 ±15.5 80.3 ±15.6 -
VT2 (% VO2max) 72.5 ±7.8 72.3 ±5.5 70.6 ±8.5 78.7 ±6.0 * <0.001
Absolu e VO2a
VT2(L/min) 1.5 ±0.5 1.6 ±0.5 1.7 ±0.5 2.0 ±0.7 * 0.017
Rela i e VO2a
VT2 (mL/kg/min) 17.3 ±3.5 18.7 ±3.1 20.8 ±5.3 24.7 ±7.1 * 0.016
VO2max (L/min) 2.0 ±0.6 2.2 ±0.6 2.38 ±0.8 2.5 ±0.8 0.579
VO2max
(mL/kg/min) 24.0 ±4.7 25.9 ±4.8 29.7 ±7.8 31.4 ±8.5 0.635
Daily calo ic in ake
(kcal) 1519 ±563 1518 ±500 1539 ±493 1555 ±403 0.967
* S a is ically signi ican (p< 0.05) di e ence a pos -in e en ion be ween g oups.
In . J. En i on. Res. Public Heal h 2022,19, 3962 8 o 13
3.1. Changes in VT2
VT
2
was exp essed as a pe cen age o absolu e VO
2
max (L/min), as p esen ed by
p e ious s udies [
15
,
26
,
27
]. A epea ed measu es ANCOVA analysis indica ed a s a is ically
signi ican di e ence in VT
2
change a pos exe cise in e en ion (p< 0.001) be ween aining
g oups. Following he 12-week exe cise in e en ion, VT
2
wi hin he indi idualised g oup
demons a ed a mean imp o emen om p e- o pos -exe cise in e en ion o 70.6
±
8.5%
o 78.7
±
6.0%, which was signi ican ly g ea e in compa ison o he s anda dised exe cise
g oup 72.5 ±7.8% o 72.3 ±5.5%.
3.2. Incidence o VT2Responde s and Non-Responde s
The p opo ion o likely esponde s and non- esponde s o an absolu e change in
VT
2
exp essed as a pe cen age o VO
2
max is p esen ed in Figu e 3a,b. The e we e 15/19
(79%) likely esponde s o a signi ican meaning ul change in VT
2
in he indi idualised
exe cise g oup, while only 9/19 (47%) pa icipan s in he s anda dised exe cise g oup we e
ecognised as likely esponde s. A Chi-squa e es indica ed a signi ican di e ence in he
p opo ion o esponde s be ween he wo aining g oups (p= 0.04).
In . J. En i on. Res. Public Heal h 2022, 19, x 8 o 13
3.1. Changes in VT2
VT2 was exp essed as a pe cen age o absolu e VO2max (L/min), as p esen ed by p e-
ious s udies [15,26,27]. A epea ed measu es ANCOVA analysis indica ed a s a is ically
signi ican di e ence in VT2 change a pos exe cise in e en ion (p < 0.001) be ween ain-
ing g oups. Following he 12-week exe cise in e en ion, VT2 wi hin he indi idualised
g oup demons a ed a mean imp o emen om p e- o pos -exe cise in e en ion o 70.6
± 8.5% o 78.7 ± 6.0%, which was signi ican ly g ea e in compa ison o he s anda dised
exe cise g oup 72.5 ± 7.8% o 72.3 ± 5.5%.
3.2. Incidence o VT2 Responde s and Non-Responde s
The p opo ion o likely esponde s and non- esponde s o an absolu e change in VT2
exp essed as a pe cen age o VO2max is p esen ed in Figu e 3a,b. The e we e 15/19 (79%)
likely esponde s o a signi ican meaning ul change in VT2 in he indi idualised exe cise
g oup, while only 9/19 (47%) pa icipan s in he s anda dised exe cise g oup we e ecog-
nised as likely esponde s. A Chi-squa e es indica ed a signi ican di e ence in he p o-
po ion o esponde s be ween he wo aining g oups (p = 0.04).
(a)
Figu e 3. Con .
In . J. En i on. Res. Public Heal h 2022,19, 3962 9 o 13
In . J. En i on. Res. Public Heal h 2022, 19, x 9 o 13
(b)
Figu e 3. VT2 absolu e change pos indi idualised (a) and s anda dised (b) exe cise in e en ion.
4. Discussion
The main aim o his s udy was o compa e he e icacy o indi idualised and s and-
a dised exe cise p esc ip ion on o e all VT2 change among physically inac i e adul s. As
hypo hesised, he indi idualised exe cise p esc ip ion was mo e e ec i e in inc easing
VT2 compa ed o s anda dised exe cise p esc ip ion in physically inac i e adul s. This is
suppo ed by ou sub-analysis, which showed ha he indi idualised exe cise g oup e-
sul ed in signi ican ly mo e likely esponde s (15/19, 79%) o a posi i e change in VT2
(>1.9%) om p e- o pos -in e en ion, when compa ed o he s anda dised exe cise in e -
en ion g oup (10/19, 47%). To he bes o he au ho s’ knowledge, his is he i s s udy
o implemen a speci ic h eshold o VT2 esponse and di ec ly compa e s anda dised and
indi idualised exe cise p esc ip ion on di ec VT2 change among physically inac i e
adul s. The indings o his s udy a e o signi icance as inc eases in VT2 could lead o an
imp o ed abili y o ole a e highe in ensi ies o exe cise [26]. Such ou come is di ec ly
ecognised o imp o e one’s unc ional abili y o pe o m ac i i ies o daily li ing, ca di-
o ascula heal h, and o e all all-cause mo ali y [7,8,28].
P e ious li e a u e has es ablished ha pa icipan s who ake pa in highe in ensi-
ies o exe cise demons a e a g ea e change o VT2 in compa ison o hose who pa ici-
pa e in lowe in ensi y exe cise aining [15,27]. Mo e speci ically, exe cise conduc ed a
an in ensi y nea o a VT2 is an adequa e aining s imulus o imp o e VT2 among phys-
ically inac i e indi iduals [29]. This could possibly explain why he indi idualised ap-
p oach o exe cise p esc ip ion has shown o be mo e e icacious in elici ing a a ou able
VT2 esponse ela i e o a s anda dised exe cise p esc ip ion in he p esen s udy.
P e ious li e a u e has also suppo ed he use o indi idualised exe cise p esc ip ion
in elici ing a posi i e aining esponse among a ious ca dio ascula heal h measu es
[18,30]. Speci ically, indi idualised exe cise p esc ip ion is ecognised o ha e a p o-
nounced posi i e impac on CRF when compa ed o s anda dised exe cise p esc ip ion
[30]. Key ma ke s o ca dio ascula heal h and disease isk ha e also been es ablished o
be posi i ely in luenced by indi idualised exe cise p esc ip ion, signi ican ly mo e so
han s anda dised exe cise p esc ip ion [18].
Figu e 3. VT2absolu e change pos indi idualised (a) and s anda dised (b) exe cise in e en ion.
4. Discussion
The main aim o his s udy was o compa e he e icacy o indi idualised and s an-
da dised exe cise p esc ip ion on o e all VT
2
change among physically inac i e adul s.
As hypo hesised, he indi idualised exe cise p esc ip ion was mo e e ec i e in inc easing
VT
2
compa ed o s anda dised exe cise p esc ip ion in physically inac i e adul s. This
is suppo ed by ou sub-analysis, which showed ha he indi idualised exe cise g oup
esul ed in signi ican ly mo e likely esponde s (15/19, 79%) o a posi i e change in VT
2
(>1.9%) om p e- o pos -in e en ion, when compa ed o he s anda dised exe cise in e -
en ion g oup (10/19, 47%). To he bes o he au ho s’ knowledge, his is he i s s udy o
implemen a speci ic h eshold o VT
2
esponse and di ec ly compa e s anda dised and
indi idualised exe cise p esc ip ion on di ec VT
2
change among physically inac i e adul s.
The indings o his s udy a e o signi icance as inc eases in VT
2
could lead o an imp o ed
abili y o ole a e highe in ensi ies o exe cise [
26
]. Such ou come is di ec ly ecognised o
imp o e one’s unc ional abili y o pe o m ac i i ies o daily li ing, ca dio ascula heal h,
and o e all all-cause mo ali y [7,8,28].
P e ious li e a u e has es ablished ha pa icipan s who ake pa in highe in ensi ies
o exe cise demons a e a g ea e change o VT
2
in compa ison o hose who pa icipa e
in lowe in ensi y exe cise aining [
15
,
27
]. Mo e speci ically, exe cise conduc ed a an
in ensi y nea o a VT
2
is an adequa e aining s imulus o imp o e VT
2
among physically
inac i e indi iduals [
29
]. This could possibly explain why he indi idualised app oach
o exe cise p esc ip ion has shown o be mo e e icacious in elici ing a a ou able VT
2
esponse ela i e o a s anda dised exe cise p esc ip ion in he p esen s udy.
P e ious li e a u e has also suppo ed he use o indi idualised exe cise p esc ip ion in
elici ing a posi i e aining esponse among a ious ca dio ascula heal h measu es
[18,30]
.
Speci ically, indi idualised exe cise p esc ip ion is ecognised o ha e a p onounced posi-
i e impac on CRF when compa ed o s anda dised exe cise p esc ip ion [
30
]. Key ma ke s
o ca dio ascula heal h and disease isk ha e also been es ablished o be posi i ely in-
