Substituting Sitting With Standing and Walking in Free-living Conditions Improves Daily Glucose Concentrations in South Asian Adults Living With Overweight/Obesity
Phase: NA
Conditions: Cardiovascular Risk Factor, Cardiovascular Diseases, Diabetes, Type 2 Diabetes, Sedentary Behavior, Sedentary Lifestyle
Sponsor: University of Bedfordshire

1 
 
 
Unique Protocol ID: 
2020ISPAR006 
NCT Number: NCT04645875 
Date of Approval: 24th June 2020 
Date of Compilation: 30th December 2025  
Please note: All information is provided based on the pre-approved ethics, approved on 24th June 2020 
(approval confirmation attached at the end of this document).  
 
Study title: Substituting Sitting with standing and Walking in Free-living Conditions Improves Daily 
Glucose Concentrations in South Asian Adults Living with Overweight/Obesity 
 
Brief Title: Substituting sitting with standing and walking in Free-living Conditions improves daily 
glucose profile in South Asians 
 
 
Study aim: 
 
The purpose of this study is to investigate the effects of substituting sitting under free-living conditions in 
South Asian adults with overweight and obesity on continuous glucose profiles. 
 
 
Methods 
Study overview 
This was a randomised crossover design study with two activity regimens (SIT and SITless) undertaken 
in free-living conditions. The study was conducted according to the Declaration of Helsinki principles and 
approved by the University of Bedfordshire Institute for Sport and Physical Activity Research Ethics 
Committee (2020ISPAR006). Participants provided written informed consent to take part. The study was 
conducted and reported in line with the Consolidated Standards of Reporting Trials guidance. The trial 
was registered with clinicaltrials.gov/(NCT04645875). Experimental regimen order was randomised using 
an online computer-generated randomisation method (https://www.randomizer.org/). Following a 
preliminary testing visit and successful try-out-day, participants completed two experimental regimens, 
each lasting 4 days, with a 3 day washout period between to minimise potential carryover effects. 
 
Participants 
South Asian adults living in the UK aged 18 to 75 years living with overweight or obesity (BMI > 23 kg 
m−2) were eligible to take part. The BMI thresholds were aligned with overweight/obesity-related 
comorbidities among South Asian populations and calculated as body mass (kg)/height (m)2. ‘South 
Asian’ was defined as anyone identifying themselves as South Asian or British South Asian. Exclusion 
criteria were self-reported CVD, current diagnosis of COVID-19, diabetes, a known blood-borne disease, 
pregnancy, recent or current smoker and other health issues (e.g., neurological disorders) or physical 
limitations that might limit the ability to perform the required volume of LPA. Participants were recruited 
from the local community (Luton and Bedford, UK) using adverts through social media posts (e.g., 
Facebook and Twitter) and distribution of flyers. 
 
Sample size calculations 
A-priori sample size was calculated using G*Power version 3.0.10. The primary outcome was postprandial 
glucose (mmol L−1) with the mean effect size taken from previous lab-based studies in participants with 
overweight and obesity (d = 0.9; Dey et al. 2024; Dunstan et al. 2012; Henson et al. 2016). A total of 11 
South Asian individuals living with overweight/obesity were required to achieve 80% power with an alpha 
value of 5%. Recruitment targeted 14 participants to allow for 20% dropout. 
 
 
  
Detailed Description: 
 
Anthropometric measurement tools, including a stadiometer, a measurement tape and a digital weighing 
scale, an activity monitor and a Flash Glucose Monitor and sensor, were posted to the participants' home 
or workplace or the research team dropped all these items at participants' doorstep to allow participants to 

2 
 
 
take their measures including height, weight, and waist circumference. 
 
Participants performed a try-out day of the SITless regimen after preliminary testing and before the first 
experimental regimen. Participants were only eligible for inclusion if they were able to adhere to the 
experimental protocol (i.e., substitute a minimum of 5-h/day sitting with ≥2-h of self-perceived light 
walking and ≥3-h of standing), assessed via monitoring with an activPAL. Participants were provided with 
a second attempt if required. 
 
After the try-out day, participants were set up with the FGM and activPAL, which were both worn 
throughout the experimental period. Setup was completed 24-h before the commencement of the first 
experimental regimen and subsequently worn for 11 days (i.e., 2* 4-day regimens and 3 days washout). 
Regimen 1 (SIT or SITless) took place over 4 days (day 1-4: Monday to Thursday), followed by a 3-day 
washout period (day 5-7: Friday to Sunday), followed by regimen 2 (SIT or SITless) for 4 days (day 8-11: 
Monday to Thursday). Participants were informed of the order of their experimental regimens and 
provided verbal and written guidance on how to complete the protocols. The experimental regimens were 
as follows: 
 
SIT regimen: Participants were instructed to restrict walking to ≤1 h/day and standing to ≤1 h/day during 
their waking day. Participants were allowed to perform their daily activities, including cooking and other 
household activities, within the 2-h of permitted walking and standing (instruction is attached below). 
 
SITless regimen: Participants were instructed to substitute a minimum of 5-h/day sitting with ≥3-h of 
standing and ≥2-h of self-perceived LPA in addition to interrupting their sitting for 2-5-min every 30-min. 
A list of activities (including walking at a slow pace, walking on the spot, jumping up and down, and 
standing) was provided as examples of activities that participants could perform during this regimen. 
Participants received feedback on their non-sitting time and the number of light and moderate-intensity 
steps from the try-out day. They were guided towards achieving compliance in this regimen by identifying 
potential activities they could engage in to interrupt sitting, reviewing their number of sitting interruptions 
and aiming to accumulate approximately 12,000 steps per day (6,000 steps being equivalent to 1-h of 
moderate-intensity walking) (instruction is attached below). 
 
Participants were asked to refrain from food and drink containing alcohol for 24-h before and to avoid 
performing structured exercise for 48-h before the experimental protocol commenced and throughout the 
entire experimental period (a total of 11-days). A kitchen scale was provided so participants could weigh 
and record all food and beverage consumption in a diary during the first 4-day regimen and replicate this 
dietary intake exactly during the second 4-day regimen. Participants were instructed to consume a 
standardised diet (at least 50% carbohydrate) in order to reduce dietary heterogeneity within the study 
population. Participants were advised that the meals were spaced evenly throughout the day with 3 to 4-h 
intervals, with snacks consumed between meals to ensure three distinct and consistent glucose responses 
across each day. 
 
 
 

3 
 
 
SIT Regimen Instructions 
 
 
Dear Participant, 
 
During the Sit regimen, we want you to sit as much as possible. Please follow these instructions from 
dates [….............................. ] to [ ............................. ] 
 
 
 
 
1. Please limit standing to a maximum of 1 hour per day and walking to a maximum of 1 hour per day 
for each of the 4 days. Spend the rest of the day sitting down. This is really important as we can then see 
how the Sitless regimen affects your health compared to days when you sit down a lot. Where 
possible please use public transport or a car to travel to and from places to limit your activity levels. 
 
Please do not engage in any structured exercise (e.g., cycling, sports, gym workout, running session etc.) or 
consume any alcohol during the whole study. 
 
Please make sure you continue your normal daily life during the 3 days between your “Sit Less” and “Sit” 
regimens. 

4 
 
 
SITless Regimen Instructions 
 
Dear Participant, 
 
During the Interrupting Sitting condition, you will be asked to follow the below instructions for each of 
the 4 days. This will take place on dates [… ...................................... ] to [ ................................ ] 
 
Each day please substitute a minimum of 5 hours per day of sitting with ≥2 hours of light-intensity physical activity 
and ≥3 hours of standing breaks. Try to spread this out over the whole day. In addition, you should try to rise from 
the seated position for 2-5 minutes every 30 minutes to engage in standing/light-intensity physical activities to 
interrupt your sitting. 
 
If you have a long commute to work, need to sit through a long meeting, or cannot stand within a particular hour 
for a different reason, that is ok as long as you replace your sitting time with at least 5 hours of standing and light 
activity over the day. 
 
Please ensure you engage in a minimum of 3 hours of standing and 2 hours of light-intensity physical activity 
(e.g. from the activities below) on each of the 4 days. 
 
Here are some suggestions for activities you can do during your breaks: 
 
• 
Walking at a slow pace 
• 
Walking on the spot 
• 
Jumping up and down 
• 
Taking the stairs 
• 
Standing (you could stand when you are unable to engage in the other activities e.g. during meetings) 
 
You will have been given a demonstration by the research team virtually. Tips to 
remember to take your breaks 
1. Download a phone app to remind you e.g. 
a. Stand Up! The Work Break Timer (Apple - recommended) 
b. Break Reminder (Android) 
c. Goodtime Productivity timer (Android - recommended) 
 
2. Download a computer app that sends reminders to your screen e.g. 
a. WorkRave (Windows – recommended) 
b. PC Workbreak (Windows) 
c. Time Out (Mac – recommended) 
d. Awareness (Windows or Mac) 
e. Break Timer (available on Chrome browser) 
 
3. Set reminders on your phone, computer or outlook calendar 
 
4. You may want to tally up how many breaks you have taken each day too! 

3 
 
 
 
5. Download a phone app to remind you e.g. 
a. Stand Up! The Work Break Timer (Apple - recommended) 
b. Break Reminder (Android) 
c. Goodtime Productivity timer (Android - recommended) 
 
6. Download a computer app that sends reminders to your screen e.g. 
a. WorkRave (Windows – recommended) 
b. PC Workbreak (Windows) 
c. Time Out (Mac – recommended) 
d. Awareness (Windows or Mac) 
e. Break Timer (available on Chrome browser) 
 
7. Set reminders on your phone, computer or outlook calendar 
 
8. You may want to tally up how many breaks you have taken each day too! 
 
Please do not engage in any structured exercise (e.g., cycling, sports, gym workout, running session etc.) or 
consume any alcohol during the whole study. 
 
Please make sure you continue your normal daily life during the 3 days between your “Sit Less” and “Sit” 
regimens. 

4 
 
Statistical analysis plan 
 
Statistical analyses were performed using SPSS version 26.0 (SPSS Inc., Armonk, N.Y., USA). Data were tested 
for normality using Q-Q plots. Linear mixed models with a compound symmetry correlation structure were used 
to determine the main effect of experimental regimen (SIT vs. SITless) for the outcome variables, with 
experimental regimen included as a fixed factor and participants included as a random factor. The models 
analysing activPAL outcomes were adjusted for activPAL wear time. The models analysing FGM outcomes 
adjusted for BMI. Two-tailed statistical significance was set at p ≤ 0.05. Cohen’s d effect sizes were calculated, 
with 0.2, 0.5, and 0.8 indicating a small, medium or large effect, respectively (Cohen 1988). All data are presented 
as mean (95% confidence interval [CI]) unless stated otherwise. 
 
 

5 
 
ISPAR Ethical Approval Confirmation