During exercise, we are constantly pushing the body to become stronger through numerous different methods. Whether you are engaging in resistance training, cardiorespiratory exercise, high intensity interval training (HIIT), or somewhere between, sleep is vital to not only recovery, but growth. During exercise, muscles throughout the body accumulate small microtears. These microtears can cause DOMS, delayed onset muscle soreness, in the areas worked. One of the best ways to combat DOMS is to get proper nutrition and proper sleep to help repair these affected areas.
How much sleep is needed for different ages? The National Sleep Foundation recommends 8-10 hours for teenagers and 7-9 hours adults. If you find it difficult to reach these numbers on a regular basis, then try limiting screentime later in the day and engaging in physical activity or resistance training. Implementing these two things have been shown to increase sleep quality through increasing deep sleep and increasing REM sleep. If you have tried these already and still find yourself not being able to get proper rest, then try increasing the intensity of your training sessions. Intense exercise has been shown to increase levels of deep sleep but decrease REM sleep.
Check out this PubMed article for a more information relating to this topic.
Interrelationship between Sleep and Exercise: A Systematic Review
PMID: 28458924 or NCBI Link