Effects of Physical Exercise Timing On Strength and Cardiometabolic Health

University of Basel152 enrolled

Overview

Physical exercise is well known to improve human health. Current guidelines provide recommendations on the frequency, intensity, type and duration of exercise. However, they do not provide recommendations for the time of day, exercise should be performed. This is surprising considering that the influence of timing of behaviors such as sleep or nutrition as well as the impact of the circadian timing system on health are well documented. Further, there is evidence for diurnal variation in maximum performance which enables individuals to exercise with different intensities at different times of day, which in the long term might affect physical adaptations to exercise. Thus, this research study investigates if exercise timing impacts human health.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

DOUBLE

Enrollment

152

Conditions

Physical Inactivity

Interventions

Eligibility

Sex: ALLMin age: 60 YearsMax age: 80 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * BMI 18.5 - 30 kg/m2 Exclusion Criteria: * Structured resistance training within the last six months * Ongoing shift work * Irregular bedtime (\> 2 hours variation in habitual bed time) * Smoking * Travels across more than two time zones within the last four weeks * Inability to follow the study procedures (e.g. due to language barriers, psychological disorders, dementia, etc.) * Known pregnancy or lactating women * Participation in any other clinical trial within the last four weeks * Medical condition that is a contra indicator for resistance training, endurance training, or exercising until maximum exhaustion including insufficiently controlled blood pressure (systolic \> 170 mmHg, diastolic \> 100 mmHg), ongoing cancer treatment, unstable angina pectoris, uncontrolled bradyarrhythmia or tachyarrhythmia, severe uncorrected valvular heart disease, clinically relevant acute infection, any form of musculoskeletal injury, orthopedic problems or decompensated cardiovascular disease * Insulin dependent diabetes * Participants using metformin

Outcomes

Primary Outcomes

Maximum strength

Mean value of the maximum isometric strength assessed at four different times of the day with an isometric mid-thigh pull on a force plate.

Time frame: Pre-Intervention (i.e. 1 to 28 days before the first training session of the exercise intervention) and Post-Intervention (i.e. 1 to 28 days after the last training session of the exercise intervention)

Secondary Outcomes

Glucose control

2-h postprandial area under the curve for glucose after an oral glucose tolerance test

Body composition

total body fat mass assessed with DXA

Cardiorespiratory fitness

VO2max assessed with cardiopulmonary exercise test