Melatonin is a hormone that plays an important role in regulating the sleep-wake cycle. As we age, the levels of melatonin in the body decrease. This decline in melatonin is thought to contribute to the sleep disturbances often experienced by older adults. In this article, we will examine at what age melatonin levels start to decline and the impact this has on sleep quality.
What is Melatonin?
Melatonin is a hormone produced by the pineal gland, a small gland located in the brain. Melatonin helps regulate the sleep-wake cycle by causing drowsiness and lowering core body temperature, which enables sleep. Melatonin levels begin to rise in the evening as part of the body’s natural preparation for sleep. Levels peak in the middle of the night during normal sleep and then decline towards morning as the body begins to prepare for wakefulness.
In addition to regulating sleep, melatonin also acts as a powerful antioxidant with health benefits. It helps boost immune function, reduce inflammation, and protect against certain cancers and age-related diseases. Melatonin supplements have become popular as a sleep aid and for other potential health benefits.
When Does Melatonin Production Begin to Decline?
Melatonin production remains high during childhood and peaks between ages 10-20. Somewhere between the ages of 30-50, melatonin levels start to decline significantly.
By age 65, the average nighttime melatonin levels are only a third of what they were at age 20. This marked decrease continues as people advance in years.
Some studies have found almost negligible amounts of nighttime melatonin in people over the age of 70. However, research shows that daytime melatonin levels remain stable with aging.
Age Ranges of Melatonin Decline
Here is an overview of the typical melatonin reductions at different age ranges:
Age Range | Melatonin Decline |
---|---|
30-50 years | Melatonin begins to decline but nighttime levels are still robust |
50-65 years | Melatonin levels drop by up to 50% at night |
Over 65 years | Nighttime melatonin is reduced by over 75% compared to young adulthood |
As shown, melatonin reduction is a gradual process but becomes quite significant by the mid-60s and beyond.
Factors Contributing to Melatonin Decline
There are several factors that contribute to the age-related decline in melatonin:
Decreased Melatonin Production
As people get older, the pineal gland calcifies and shrinks. This inhibits the production of melatonin. The enzymes and precursors needed for melatonin synthesis also decline with age.
Deterioration of Circadian Rhythm
Our circadian rhythm is our internal 24-hour clock that regulates sleep-wake cycles. Aging leads to decreased circadian rhythm amplitude and disjointed cycles. Since melatonin is controlled by the circadian clock, disruptions in the circadian rhythm impair melatonin release.
Reduced Melatonin Clearance
With aging, the body metabolizes and clears melatonin more slowly. This can lead to high daytime melatonin levels. When melatonin remains elevated during the day, it can make older people feel excessively sleepy and confused.
Medications
Many commonly used medications in older adults, like blood pressure medications and antidepressants, have side effects that suppress melatonin. Nighttime use of these drugs can exacerbate the natural melatonin decline.
Diseases
Medical conditions like Alzheimer’s disease, diabetes, and cancer are associated with impaired melatonin rhythms and production. Inflammatory processes may also inhibit melatonin release.
Consequences of Melatonin Decline
The age-related decline in melatonin has significant adverse effects on health and wellbeing:
Impaired Sleep
With less melatonin, many people find it harder to fall asleep and stay asleep. Older adults often experience more nighttime awakenings and less restorative sleep. Disturbed sleep at night leads to daytime fatigue and cognitive issues.
Disrupted Circadian Rhythms
The circadian system loses synchrony with diminshed melatonin. Older adults often experience altered sleep timing, like going to bed earlier, waking earlier, and napping more. Circadian misalignments are linked to depressed mood, diabetes, obesity, and heart disease.
Increased Oxidative Stress
Melatonin has potent antioxidant activity. Lower levels are associated with more oxidative damage and higher inflammation. This accelerates aging and disease processes.
Weakened Immune Function
Melatonin interacts with the immune system. Decreased melatonin is tied to weakened immunity and higher infection susceptibility in the elderly.
Increased Cancer Risk
Melatonin has oncostatic properties, meaning it can inhibit tumor growth. Declining melatonin removes this protective effect, increasing cancer risk.
Strategies to Increase Melatonin
While melatonin reduction is an inevitable part of aging, there are strategies to help boost melatonin levels as we get older:
Increase Light Exposure During the Day
Exposure to bright light during the day enhances circadian rhythm strength and melatonin production at night. Older adults should get morning sunlight and sit near windows during the day.
Limit Blue Light Exposure at Night
Blue light from electronics and screens suppresses melatonin. Avoid screen use for 2-3 hours before bedtime. Consider blue light blocking glasses.
Establish Regular Sleeping Habits
Keeping a fixed sleep schedule reinforces the circadian clock and maximizes melatonin release. Try to sleep and wake at consistent times, even on weekends.
Sleep in Complete Darkness
Any ambient light at night impedes melatonin release. Ensure the bedroom is completely dark with blackout curtains. Turn off all lights.
Take Melatonin Supplements
Low-dose melatonin supplements before bedtime can help raise melatonin levels. However, always consult a doctor first.
Avoid Alcohol and Smoking
Both alcohol and nicotine impair melatonin production. Limiting evening intake can help optimize sleep-promoting melatonin.
Consider Food Choices
Some foods and drinks have naturally occurring melatonin, like tart cherry juice, pistachios, and tomatoes. Incorporating these into the diet may support melatonin levels.
The Bottom Line
Melatonin levels start declining in mid-to-late adulthood, with the most significant reductions after age 65. This contributes to poorer sleep quality and circadian rhythm disruption in seniors. While some melatonin loss is expected, certain lifestyle tweaks and treatment strategies can help counteract the decrease and improve sleep. Consulting a doctor is advised when considering melatonin supplementation. With proper guidance, older adults can optimize their sleep-wake cycles through melatonin modulation.