Moderate exercise before going to sleep does not prevent you from sleeping well · Inserm, Science for Health

In order not to impair the quality of your sleep, it is often not advisable to exercise in the evening. However, a recent study conducted at the University of Caen-Normandy shows that moderate physical activity performed one hour before falling asleep has only a minor impact on sleep efficiency. Therefore, late physical activity remains an acceptable option if this is the only time of day available to counteract a sedentary lifestyle.

For your health and well-being, it is recommended to practice 30 minutes of moderate to high-intensity exercise at least 5 days a week – but if possible not right before bed. In fact, studies suggest that physical activity leads to physiological arousal at the end of the day, which can disrupt sleep. However, for some people, the only time to exercise is in the evening, after work. This precaution may lead them to avoid exercise, even though the results of studies on the effects of late physical activity are not unanimous. In this role: Joy Perrier, researcher InsertNicolas Bessot and members of her team at the University of Caen began to reevaluate the connection between physical activity before sleep and sleep.

endurance or resistance

To do this, they recruited healthy young adults. One hour before bedtime, they were asked to cycle for 30 minutes at a moderate intensity (endurance training), or to cycle for 30 minutes at a more intense but intermittent pace (resistance training), or finally to remain inactive (control). The exercises were calibrated so that each person expended the same amount of energy during the activity tests. All volunteers completed each task once, seven days apart.

At the same time, researchers monitored several physiological and brain parameters related to participants’ sleep. On the one hand, they measured their cortisol levels (the “waking hormone”) after 30 minutes of exercise or rest. On the other hand, they performed polysomnography, a multimodal sleep recording study that specifically includes measurements of brain activity via electroencephalogram, muscle activity, eye movements, breathing and oxygen saturation. This study made it possible to extract from the subjects the parameters associated with sleep quality and quantity – we talk about “sleep efficiency” – as well as cortical activity during the night.

Physiological and cerebral excitability without consequences

These analyzes show an increase in cortisol levels after physical activity compared to the value measured after the volunteers simply remained seated. Cortical activity during sleep is also altered by exercise. “ Depending on the sleep phases (transitional, light sleep or deep sleep), the different wave types recorded have profiles that suggest cerebral hyperexcitability », specifies Joy Perrier. However, despite these changes induced by exercise (endurance and resistance), there is little change in sleep efficiency: “ It only decreases by 1.5%. It is ridiculous! However, this shouldn’t stop you from getting a little exercise before the night if that’s the only time available during the day. », comments Nicolas Bessot. “ However, at this point it is difficult to generalize this resultcontinues Joy Perrier. We only studied young, healthy individuals: these analyzes deserve to be reproduced in other populations, older people, suffering from sleep disorders or even suffering from certain diseases. “, She believes.

Joy Perrier is an Inserm researcher in the department Neuropsychology and imaging of human memory