International Longevity Centre Global Alliance - Designing the Future of Ageing

6th May 2026

Research by Gali Albalak explored how the timing of physical activity affects sleep, mood and health in adults aged 60 to 80 years with sleep difficulties. The study found that morning exercise was associated with earlier bedtimes, improved mood and higher energy levels.

On 6 May 2026, Gali Albalak, Coordinating Researcher at Leiden University Medical Center, successfully defended her PhD thesis, Getting Older Adults Moving at the Right Time. The central question of her research was: What is the best time of day to be physically active? The study examined adults aged 60 to 80 years who experienced sleep difficulties and investigated how exercising at different times of the day affects sleep quality and other aspects of health, including metabolism and mood.

Why this research?

Previous studies have consistently shown that physical activity plays a vital role in maintaining health and vitality. Given its importance, national physical activity guidelines have been established in the Netherlands, recommending at least 30 minutes of moderate-intensity physical activity on five or more days each week. These guidelines specify how often, how long and how intensively people should be active to support their health. However, they do not indicate the optimal time of day for physical activity.

Recent research suggests that timing may matter. This is linked to our biological clock, an internal system that regulates the body’s 24-hour daily rhythm. A well-functioning biological clock is essential for overall health. Both nutrition and physical activity, when timed appropriately, can help synchronise bodily processes with this internal rhythm. Until now, however, it remained unclear when physical activity might be most beneficial.

“Many participants remained physically active after the study ended. Exercising in a group setting also had a positive effect on social connectedness.”
Gali Albalak, Coordinating Researcher

Morning Exercise Benefits Mood

The OP TIJD study built on earlier research conducted by Leyden Academy into peer coaching within the Vitality Club. Many older adults experience challenges related to their sleep–wake rhythm. For example, they may have difficulty falling asleep or feel drowsy during the day. Previous studies have shown that spending time outdoors early in the morning and engaging in physical activity can have beneficial effects in this area. The Vitality Club combines these two approaches, but their impact on sleep quality and biological rhythms among older adults had not previously been investigated.

The findings of the OP TIJD study show that the timing of physical activity influences sleep patterns. Participants who exercised in the morning tended to go to bed slightly earlier than those who exercised in the evening. The study also found that morning exercise was associated with improvements in mood and energy levels.

A summary of the dissertation, IT IS TIME: Implications of Chronoactivity for Disease and Health, is available here. The full dissertation is also available online in English.

The OP TIJD study was initiated by the Department of Internal Medicine for Older People at the Leiden University Medical Center in collaboration with Leyden Academy on Vitality & Ageing, the Bioclock Consortium and the Centre for Human Drug Research.

Gali Albalak, Coordinating Researcher, g.albalak@lumc.nl