Why do senior citizens aged 60+ have erratic sleeping habits?

As you age, your body makes lower growth hormone levels, so you will likely experience a reduction in slow-wave or deep sleep (an incredibly vital part of the sleep cycle). When this happens, you make less melatonin, meaning you will often experience more fragmented sleep and wake up more during the night. That’s why many of us consider ourselves “light sleepers” as we age. It is wise to go to sleep earlier in the evening and wake up earlier in the morning.
This way, you do not have to spend longer in bed at night to get the hours of sleep you require or make up the shortfall by taking a nap during your day. Such sleep changes are expected in most cases and don’t mean a sleep problem.