Older Adults Exercising On Time

There are indications from epidemiological cohort studies and animal experiments that timing of physical activity (also referred as "chronoactivity"), irrespective of intensity, impacts health and disease. In view of the detrimental effects of circadian misalignment, the large group of older people suffering from sleep problems, and the seeming importance of chronoactivity, the investigators will perform a randomised cross-over study that aims to uncover the effect of timing of physical activity on insomnia severity and related(circadian) health parameters in older adults with self-reported sleep problems. Here, the investigators hypothesize that timing of physical activity has a beneficial impact on insomnia symptoms and on circadian rhythms of additional health parameters (e.g., metabolic, psychosocial) in older people. To study this research hypothesis, the investigators will examine the effect of physical activity timing on insomnia severity in older adults with self-reported sleep problems. In addition, the investigators will examine the effect of physical activity timing on exploratory rhythmic parameters of biological clock function, physiology and metabolism, mental health, behavioural factors, and immune and cell signalling functions. For this study, a two-armed randomised cross-over study, Dutch speaking older adults between 60 and 80 years old (male and female) and having sleep problems (insomnia severity index\>10 points) from the general population in the Netherlands will be selected as participants for this study. Participants will perform one sedentary period and two period of increased physical activity with different daily patterns: 1)active morning; 2) active evening with a duration of 14 days each. In both active intervention arms, participants will follow an exercise program containing outdoor physical exercise sessions (Vitality Club) containing endurance and strength exercises, relative rest days of 30 minutes light intensity physical activity, and one Active@Home program; a 1-hour training session of various moderate to vigorous activities. The training sessions will be held either in the morning or evening (depending on the intervention arm) and will be one hour long. Study outcomes will be compared between the different intervention groups.


Eligibility Criteria:
Inclusion Criteria:

* Aged between 60 and 80 years old
* Retired
* Long lasting sleep problems (as assessed by a the screening questionnaire administered telephonically and by the ISI which will be filled out during the screening visit)
* Access to and ability to use a smart phone (Android or Apple)

Exclusion Criteria:

* Currently employed or working
* Extreme sleep chronotypes (measured by the Munich chronotype questionnaire)
* Participation in any sort of fasting regimen (e.g. intermitted fasting or Ramadan)
* Experienced recent (\<6 months) adverse life events (e.g., death of partner)
* Abnormal values in glucose metabolism, thyroid, liver or kidney function, or inflammation markers that after examination of the study doctor need immediate attention of a general practitioner or specialist.
* Diagnosed clinical depression
* Diagnosed neurodegenerative diseases (e.g. dementia or Parkinson's disease)
* Diagnosed sleep apnoea
* Diagnosed restless legs syndrome
* Use of beta-adrenergic blocking agents
* Use of sleep medication\*
* Injuries or other severe physical conditions (such as active arthrosis) that inhibits physical activity
* Travelled across time zones one week prior to start of study