Aim for 7 to 9 hours of sleep a night to recover from training
Added
Treat sleep as part of your training plan. Adults need 7 to 9 hours a night, and that doesn't drop with age, even though older adults often sleep less deeply and wake more easily. If you struggle to get up, lose focus or doze off during the day, look at your sleep before adding miles.
The result
Result: MedlinePlus (NIH): adults 18 and older need 7-9 hours a day; there is no evidence that adults need less sleep as they age, and sleep releases growth hormone that helps muscle repair.
Note: Not medical advice. Talk to your doctor before changing your training, diet, or supplements.
Source
MedlinePlus: Healthy Sleep (opens the original source in a new tab). Check it for the latest numbers before you act.