ClinicalTrials.gg
CompletedNCT06141512Updated Apr 29, 2026

Improvements in Aerobic Fitness With Exercise Training: the Role of Myokines

An interventional study of Reduced-exertion high-intensity interval training (REHIT) in General Health, sponsored by University of Stirling. Completed at 1 site in United Kingdom. Open to male participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-29.

Sponsored by University of Stirling · Not applicable, Interventional, and Prevention

Phase
Not applicable
Study type
Interventional
Enrollment
21
Allocation
Not applicable
Ages
18 Years to 40 Years
Sex
Male
01

Study summary

For both healthy adults and patients with cardiovascular disease (CVD), aerobic fitness (V̇O2max) is a stronger predictor of the risk of future chronic disease and premature death than other established risk factors such as hypertension, smoking, or Type 2 diabetes. It is important to improve the understanding of the regulation of V̇O2max to enable optimisation of interventions aimed at increasing V̇O2max in the current predominantly sedentary population. Currently, only exercise training is a viable method for increasing V̇O2max. However, \~10-20% of people who follow fully supervised, standardised training interventions do not demonstrate a measurable increase in V̇O2max. Low response to training is a clinically relevant concern, but the large variability in response to exercise training also provides an opportunity to dissect out the molecular mechanisms responsible for adaptations to V̇O2max by contrasting low vs. high responders to training. It has been previously demonstrated that low responders for VO2max fail to up regulate a number of genes that encode putative 'myokines', while the high responders demonstrated a significant increase in the expression of these genes, suggesting these myokines may play an important mechanistic role in modulating VO2max. The aim of the present study is to examine whether low responders for VO2max have an attenuated increase in the plasma levels of the previously identified myokines.

Read the detailed description

For both healthy adults and patients with cardiovascular disease (CVD), aerobic fitness (V̇O2max) is a stronger predictor of the risk of future chronic disease and premature death than other established risk factors such as hypertension, smoking, or Type 2 diabetes. Considering the large medical and economic burden of physical inactivity-related chronic disease it is important to improve the understanding of the regulation of V̇O2max to enable optimisation of interventions aimed at increasing V̇O2max in the current predominantly sedentary population. Furthermore, there is a need to identify novel drug targets to aid pharmacological intervention in those individuals who are unwilling or unable to improve V̇O2max through exercise.

Currently, only exercise training is a viable method for increasing V̇O2max. However, although exercise training on average improves V̇O2max, \~10-20% of people who follow fully supervised, standardised training interventions do not demonstrate a measurable increase in V̇O2max. Low response to training is a clinically relevant concern, but the large variability in response to exercise training also provides an opportunity to dissect out the molecular mechanisms responsible for adaptations to V̇O2max by contrasting low vs. high responders to training.

Using this approach it has previously been shown that in skeletal muscle samples obtained pre- and post- training, 86 genes are differentially regulated in high compared to low responders for V̇O2max. Strikingly, out of these 86 genes, 13 genes encode proteins that have been reported to be released by muscle during or after exercise (i.e., 'messenger proteins' termed myokines). This strongly suggests low responders to exercise training fail to sufficiently upregulate the production and release of these myokines, and that this is (at least partly) the reason why these people do not manage to improve their V̇O2max as much as high responders. However, in order to confirm a mechanistic role of these myokines in increasing V̇O2max, it needs to be demonstrated that beside the change in gene expression, the change in the plasma levels of these myokines is also impaired in low responders for V̇O2max.

02

Conditions studied

  • General Health

Keywords

  • VO2max
  • Myokine
  • Cardiorespiratory Fitness
03

In context

Lead sponsor

University of Stirling is the lead sponsor of 23 studies on the registry; 2 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 40 Years
Sexes eligible
Male
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Male
  • Age ≥ 18 y or \<40 y
  • \< 35 kg/m2
  • otherwise healthy, untrained individuals

Exclusion criteria

Exclusion Criteria:

  • Age \<18 y or >40 y
  • > 35 kg/m2
  • classification of 'highly physically active' according to the International Physical Activity Questionnaire (IPAQ)
  • answering 'yes' to one or more questions on a standard Physical Activity Readiness Questionnaire (PAR-Q)
  • resting heart rate ≥100bpm, hypertension (140/90 mmHg)
  • a personal history of metabolic or cardiovascular disease
  • Female participants because of unknown effects of the menstrual cycle on the levels of the measured myokines.
Terms in these criteria, in plain language(2)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

BMI (body mass index)

Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.

What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

05

Study design

Phase
Not applicable
Primary purpose
Prevention
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
21 participants (actual)

Study arms

  • Experimental
    Reduced-exertion high-intensity interval training (REHIT)

    All participants complete 6 weeks (3 sessions/week) of an exercise intervention labelled 'REHIT'. Exercise sessions involve 10 minutes of unloaded cycling interspersed with 2 x 20 sec 'all-out' sprints against a resistance of 7.5% of participant's body weight. Sprints begin at 1:40 min and 5:40 min.

    Behavioral: Reduced-exertion high-intensity interval training (REHIT)

Interventions

  • BehavioralReduced-exertion high-intensity interval training (REHIT)

    Description same as Arm description.

    Also known as: Sprint interval training (SIT)

06

What researchers measure

Primary outcomes

  1. Training induced changes in VO2max

    Maximal aerobic capacity (VO2max) will be measured pre- and post-training to determine the change in VO2max.

    Time frame: Pre-intervention and 3 days post-intervention

  2. Training induced changes in plasma myokines

    Plasma myokine levels of 8 myokines will be measured pre- and post-training to determine the change in plasma myokine levels.

    Time frame: Pre-intervention and 3 days post-intervention

07

Study locations

1 site
  • University of Stirling
    Stirling, FK9 4LA, United Kingdom
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reached

Ran from Oct 2023 to primary completion in Jun 2024, 8 months.

How these figures are worked out, and which studies are left out of them.

Registered
Nov 13, 2023
First posted
Nov 21, 2023
StartActual
Oct 23, 2023
Primary completionActual
Jun 30, 2024
CompletionActual
Jun 1, 2025
Last update
Apr 29, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Apr 29, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT06141512
Lead sponsor
University of Stirling
Responsible party
Niels Vollaard (Principal Investigator, University of Stirling) — Principal investigator
First posted
Nov 21, 2023
Start date
Oct 23, 2023
Primary completion
Jun 30, 2024
Completion
Jun 1, 2025
Last update
Apr 29, 2026

Study contacts

Niels Vollaard, PhD
principal investigator · University of Stirling

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.

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