The daily target of 10,000 steps is popular, but a 2016 study suggests that there are health benefits from a lower number particularly where the steps are more intense and that limiting the amount of time sitting or being inactive is also beneficial. Another 2016 study suggests that "interrupting sitting time improves blood sugar control in people with type 2 diabetes".
A 2016 study suggests that short-term sleep deprivation can affect heart function and this has implications for those doing shift work and those who struggle to get good quality sleep.
Some advice from the scholars
Ibn Qayyim Al-Jawziyya in Medicine of the Prophet the subject of exercise from the view of helping the body get rid of the waste products of digestion and helping it remove obstructions. He advises that movement helps digestion and evacuation by warming the body. He recommends a moderate amount of exercise, at the proper time along with other correct lifestyle habits.
The proper time for exercise is after food has digested.
Moderate exercise is when the skin is red and body is moist. Ibn Qayyim advises that when sweat pours down the body that is excessive.
Ibn Qayyim advises that for every limb and faculty (including the soul and the brain) there is an exercise.
Ibn Qayyim notes that the standing in prayer by night is one of the most beneficial things to preserve health and prevent illness.
As-Suyuti in Medicine of the Prophet advises that exercise should stop when the sweating starts.
Ibn Sina is quoted as saying in “Avicenna’s Medicine” that exercises should be varied and also suitable for one's age, strength and medical condition. He outlines massage, warm-up and warm-down rules and suggests that in certain types of individual exercise may cause disease.
Image: By Mike H from Seattle, USA - Tai chi, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4679243