Sleep and your hormones

The daily rhythm: melatonin and cortisol

Your internal clock runs on a roughly 24-hour cycle tuned by light and darkness. The National Heart, Lung, and Blood Institute explains that the brain releases melatonin based on the light-dark cycle. Levels start rising in the evening and peak in the early morning, helping promote sleep.

Cortisol does the opposite job. It rises as morning approaches and helps prepare your body to wake. Bright light late in the evening, including from screens, can suppress melatonin and make it harder to fall asleep, while morning daylight helps anchor the rhythm.

Estrogen, progesterone and the menopause transition

Trouble falling or staying asleep is one of the most common complaints of perimenopause, and the Office on Women's Health lists it among core menopause symptoms. Night sweats are a big part of the problem: a surge of heat and sweating wakes you, and getting back to sleep can take a long time.

Hormone shifts can also disturb sleep without obvious sweating. Many women describe waking with a racing heart or a jolt of anxiety. Mood changes, bladder urgency and joint aches, all common during the transition, add further awakenings.

Menopause and sleep apnea

Before menopause, women have a lower risk of obstructive sleep apnea than men. NHLBI notes that risk rises during and after menopause, partly due to hormone changes and weight gain around the neck. Because women with apnea more often report insomnia, fatigue, morning headaches and low mood than loud snoring, it can be mistaken for menopause itself.

If your sleep has not improved after hot flashes are treated, or you snore or wake gasping, ask about a sleep evaluation.

Testosterone and sleep in men

Most of a man's daily testosterone release happens during sleep, which is why levels are highest in the morning. A small study published in JAMA in 2011 restricted healthy young men to short sleep for a week and examined their testosterone levels, adding to evidence that cutting sleep short affects this hormone. Its authors also noted that fragmented sleep and obstructive sleep apnea are associated with lower testosterone.

The Endocrine Society lists sleep disorders among conditions associated with low testosterone and advises against starting testosterone therapy in men with untreated severe sleep apnea. If your testosterone is low and your sleep is poor, the sleep problem is worth addressing first or alongside hormone testing.

Sleep, appetite and weight

The National Institute of Diabetes and Digestive and Kidney Diseases notes that too little sleep may increase hunger, calorie intake and less healthy food choices. Over months, that can contribute to the midlife weight gain many people notice, which in turn raises sleep apnea risk.

Thyroid hormone matters too. Low thyroid function can cause fatigue and weight gain and is listed by NHLBI as a risk factor for sleep apnea, which is one reason clinicians may check thyroid levels in people with poor sleep.

Does hormone therapy improve sleep?

For women whose sleep is disrupted mainly by hot flashes and night sweats, treating those symptoms often improves sleep. Hormone therapy is the most effective treatment for hot flashes, according to the Menopause Society, and non-hormonal options exist for women who cannot or prefer not to use hormones.

Hormone therapy is not a treatment for sleep apnea or for insomnia that persists after hot flashes are controlled. In men, testosterone therapy is not a sleep treatment either, and it requires monitoring for effects on red blood cells and breathing during sleep.

What a clinician may check

When sleep and hormones seem tangled together, a clinician will usually start with your history: your cycle pattern or time since menopause, night sweats, snoring, mood, alcohol, medications and work schedule. From there, testing is targeted rather than broad.

Depending on your symptoms, that may include thyroid tests, early-morning testosterone measured on two separate days for men, blood counts and iron studies for fatigue, and blood sugar. If apnea is suspected, a sleep study answers that question directly. Hormone panels are rarely needed to diagnose perimenopause itself, because levels swing too much to give a clear answer.

Habits that support both sleep and hormones

These come largely from CDC and NHLBI sleep guidance. If good habits are not enough after a few weeks, see a clinician. Seek prompt care for loud snoring with breathing pauses, sleepiness while driving, or low mood that lasts more than two weeks.

• Get outdoor light soon after waking to anchor your body clock
• Dim lights and put screens away at least 30 minutes before bed
• Keep a steady sleep and wake time, aiming for at least 7 hours in bed asleep
• Keep the bedroom cool, which also helps with night sweats
• Avoid alcohol and large meals close to bedtime, and caffeine after midday
• Do muscle-strengthening and aerobic exercise regularly, finishing intense workouts earlier in the day