Does exercising in the evening prevent you from sleeping well? A new study answers the question

If there is no other way but to make time for physical activity in the evening, after a day at work, research warns of the detrimental effects of late physical activity on sleep. This time, French researchers studied the quality and quantity of sleep in young athletes after exercising before bed. Their results confirm that evening exercise can lead to a level of neurophysiological arousal that can disrupt sleep.

Are endurance exercises more harmful than resistance exercises?

This study of 16 healthy young athletes aged 21 to 27 years used polysomnographic recordings (measurements of brain activity, movement and breathing) and salivary cortisol levels. Two types of exercise, endurance (using cardiorespiratory capacity, regular but gentle muscle contractions) or resistance (using muscle power, infrequent but strong muscle contractions), were performed for 1 hour 30 minutes before bedtime. Finally, while endurance and resistance exercise decreased sleep quantity and quality, sleep efficiency decreased following endurance exercise.

Adaptation of brain activity after physical exercise

Analysis of spectral power by electroencephalography (which records electrical activity on the surface of the brain) showed increases in alpha and theta power (electrical signals produced by the brain) during specific stages of sleep after both types of sleep. Exercises. This increase may reflect adaptive changes in nighttime brain activity in response to exercise.

But the two types of exercise produced different effects. Endurance exercise leads to increased brain activity (beta spectral power) and elevated cortisol levels, indicating hyperarousal. Resistance is associated with lower brain activity and lower cortisol levels. In summary: Endurance exercise has a more negative effect on the neurophysiology of sleep.

But be careful, although the study shows changes in sleep after nocturnal exercise, it does not consider these effects to be truly harmful, an issue that remains to be explored. For Joy Perrier, a post-doctoral student at the University of Caen, first author of the study, “These results provide valuable insight into the physiological effects of physical exercise performed in the evening and confirm warnings to avoid physical activity late in the evening and, if possible, 2 hours before bedtime.“. The Precautionary Principle.