Minimum Effective Exercise Intensity in Sedentary Individuals (MEI)

Minimum Effective Exercise Intensity for Improving Cardiorespiratory Fitness and Cardiometabolic Health in Sedentary Individuals

The aim of this randomized controlled intervention study is to examine the minimum exercise intensity that has an effect on cardiorespiratory fitness and/or cardiometabolic risk factors in sedentary adults. In addition, the study seeks to examine which background factors explain individual differences in exercise responses.

Study Overview

• Status: Recruiting
• Conditions: Sedentary Individuals Not Participating in Regular Exercise Training/Physical Activity
• Intervention / Treatment: Other: Exercise

Detailed Description

The study consists of a 2-week baseline period followed by two 6-week intervention periods. The study will compare changes in the predefined outcome variables between the exercise intervention groups and the control group that does not perform any exercise training. In addition to intensity prescribed relative to oxygen uptake reserve, exercise intensity will be retrospectively analyzed in relation to the first ventilatory threshold in order to examine the lowest effective intensity using this method as well. Among background factors, possible modifiers assumed on the basis of previous literature, will be analyzed to assess their contribution to inter-individual differences in the outcome responses. Potential main contributors are considered to be sex, the basal value of the outcome, nutritional habits, physical activity and stationary behavior outside the prescribed training, and non-invasive indicators of stress.

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Olli-Pekka S Nuuttila, PhD; Phone Number: +358505946170; Email: olli-pekka.nuuttila@ukkinstituutti.fi

Study Locations

• Finland
  • Pirkanmaa
    • Tampere, Pirkanmaa, Finland, 33500
      • Recruiting
      • UKK institute for Health Promotion Research
      • Contact: Olli-Pekka Nuuttila, PhD; Phone Number: +35850 594 6170; Email: olli-pekka.nuuttila@ukkinstituutti.fi
  • Southwest Finland
    • Turku, Southwest Finland, Finland, 20540
      • Recruiting
      • Paavo Nurmi Centre
      • Contact: Pekka Matomäki, PhD; Phone Number: +358449828506; Email: pekka.j.matomaki@jyu.fi

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 30-50-year old males and females
• Sedentary, not participating in regular exercise training/physical activity

Exclusion Criteria:

• Cardiovascular symptoms/diseases
• Musculoskeletal symptoms/diseases
• Metabolic diseases
• Resting blood pressure > 160/100 mmHg
• Body mass index ≥ 35

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control group
Experimental: 30 %/VO2reserve intervention group	Other: Exercise; 6 weeks of 3 x 30 min/week supervised cycle ergometer training and 6 weeks of 3 x 40-50 min/week supervised cycle ergometer training
Experimental: 40 %/VO2reserve intervention group	Other: Exercise; 6 weeks of 3 x 30 min/week supervised cycle ergometer training and 6 weeks of 3 x 40-50 min/week supervised cycle ergometer training
Experimental: 50 %/VO2reserve intervention group	Other: Exercise; 6 weeks of 3 x 30 min/week supervised cycle ergometer training and 6 weeks of 3 x 40-50 min/week supervised cycle ergometer training
Experimental: 60 %/VO2reserve intervention group	Other: Exercise; 6 weeks of 3 x 30 min/week supervised cycle ergometer training and 6 weeks of 3 x 40-50 min/week supervised cycle ergometer training

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal oxygen consumption	Assessed with step-ramp-step protocol	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Ventilatory thresholds	Assessed with step-ramp-step protocol	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pmax	Maximum power of the ramp cycle ergometer test	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Concentration of LDL cholesterol	Fasting state blood sample	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Concentration of HDL cholesterol	Fasting state blood sample	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Concentration of total cholesterol	Fasting state blood sample	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Concentration of triglycerides	Fasting state blood sample	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Concentration of blood glucose	Fasting state blood sample	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Concentration of insulin	Fasting state blood sample	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
HOMA-IR	(Insulin × Glucose) / 22.5	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
HbA1c	Fasting state blood sample	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Blood pressure	Systolic and diastolic blood pressure	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Resting heart rate	In sitting position	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Resting heart rate variability	Root mean square of successive differences in sitting position	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Gross efficiency	Gross efficiency during standard load	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Body weight	Measured using an electronic scale.	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Waist circumference		Pre (week 0), mid (after 6 weeks), post (after 12 weeks)

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body fat percentage	Assessed with bioimpedance	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Healthy diet index	0-100, higher score means a better outcome.	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
NEO-FFI	Psychological personality inventory	Pre (week 0)
FIMS	Finnish version of Brunel Mood Scale; It includes 24 items divided into 6 factors: tension, depression, anger, vigour, fatigue, confusion. Each factor has scale from 0 to 16, higher score meaning worse outcome. In addition total mood disturbance = summing the five negative mood dimensions and subtracting vigour. Score can be between -16 and 84 with higher score meaning worse outcome.	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
CD-RISC-25	The 25-item Connor-Davidson Resilience Scale: scoring from 0 to 100, where the higher score means better outcome.	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Estimated cardiorespiratory fitness	Ekblom-Bak test	Pre (screening phase)
Self-estimated fitness and health	One item self-estimated fitness in 1-5 scale where higher score means worse outcome; one item self-estimated health in 1-5 scale where higher score means worse outcome.	Pre (week 0), mid (after 6 weeks), post (after 12 weeks)
Non-exercise fitness test	Jackson N-eX	Pre (screening phase)
Physical/stationary behavior	Measured with an accelerometer 24/7. Physical activity will be distributed into intensity domains according to 1) ACSM 2025 description, and 2) ventilatory thresholds. Stationary behavior will be distributed into sitting, standing and lying.	Weekly averages throughout the study (Baseline + weeks 1-12)
Exercise heart rate	Heart rate during intervention exercise	Throughout the study (weeks 1-12)
Rating of perceived exertion	Estimation of perceived exertion during (6-20) and after (0-10) intervention exercises	Throughout the study (weeks 1-12)
Exercise heart rate variability	Heart rate variability response to intervention exercise and during 5-min recovery phase	Week 1, week 6, week 7, week 12
Exercise blood lactate	Blood lactate response to intervention exercise	Week 1, week 6, week 7, week 12
Exercise motivation	Exercise motivation in a 3-item scale based on Eccles' expectancy-value theory with a total score from 3 to 15, where higher score means better outcome	Week 1, week 6, week 7, week 12
State of alertness during exercise	State of alertness from a scale 1 (low alertness, relaxed) to 6 (high alertness, aroused)	Week 1, week 6, week 7, week 12
Affective responses to exercise	Feeling scale from -5 to 5 with higher value meaning more positive affective response	Week 1, week 6, week 7, week 12

Collaborators and Investigators

• Sponsor: UKK Institute
• Collaborators: Paavo Nurmi Center & Unit for Health and Physical Activity; Juho Vainion säätiö

Study record dates

Study Major Dates

• Study Start (Estimated): February 23, 2026
• Primary Completion (Estimated): December 20, 2026
• Study Completion (Estimated): December 20, 2026

Study Registration Dates

• First Submitted: January 20, 2026
• First Submitted That Met QC Criteria: February 13, 2026
• First Posted (Actual): February 18, 2026

Study Record Updates

• Last Update Posted (Actual): February 18, 2026
• Last Update Submitted That Met QC Criteria: February 13, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: exercise training; cardiorespiratory fitness; exercise intensity; cardiometabolic health
• Additional Relevant MeSH Terms: Behavior; Motor Activity; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Exercise
• Other Study ID Numbers: MINI26

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: The study involves group-based training, and complete anonymity of the results cannot be guaranteed with certainty.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No