Lt. Gen. Mahmud Ahmed Akhtar Former Surgeon General Pakistan Army
Preventive Medicine
Sleep is very important for life. Getting too little sleep, later in life, is associated with increased risk for Alzheimer’s disease. Paradoxically, so is getting too much sleep. While sleep researchers are confident that a connection between sleep and dementia exists, the nature of that connection is complicated. It could be that poor sleep triggers changes in the brain that cause dementia or people’s sleep might be disrupted because of an underlying health issue that also affects brain health. Changes in sleep patterns can be an early sign of dementia itself. Here are a few connections and how to gauge your risk based on your sleep habits.
Lt. Gen. Mahmud Ahmed Akhtar
Too Little Sleep
It has been said that sleep acts like a shower, washing away the cellular debris that accumulates during the day. During this process, the fluid that surrounds brain cells, flush out molecular garbage and transfers it into blood stream where it is then filtered by the liver and kidney and then excreted from the body. That trash includes the protein Amyloid (brain produces during the day), which is thought to play a key role in Alzheimer’s disease. Problems can arise when the Amyloid accumulates into sticky clumps, called plaques. The longer one is awake, the more Amyloid is built up and lesser the time brain has to flush it. It is not known whether regularly getting too little sleep (typically six hours or less a night) is enough to trigger the accumulation of Amyloid on its own.
• Research has found that many adults of ages 65 to 85, who already have plaques in their brain, the less sleep they got, the more Amyloid was present and worsened their cognition.
• Is the lack of sleep sufficient to cause dementia probably not by itself alone,” said Doctor Sudha Seshadri, the founding director of Glen Biggs Institute of Alzheimer’s and Neuro-degenerative Diseases at the University of Texas Health Science Center at Saint Antonia. “But it seems definitely to be a risk factor for increasing the risk of dementia”, perhaps also the speed of decline.
People with Alzheimer’s disease may start to develop symptoms in the ages 60s to 70s but Amyloid may accumulate two decades earlier. That is why it is important to prioritize sleep timing to seven to nine hours a night starting in your 40s to 50s, said Joe Winer, post-doctoral fellow of Neurology and Neurological Science in the Center of Sleep and Circadian Science at Stanford University.
Some sleep disorders, most notably Sleep Apnoea, are also associated with increased risk of dementia. That may be because sleep apnea disrupts people’s sleep or because it tends to occur in people who are over-weight or have diabetes which are also linked to dementia. Even when you remove effect of these issues of sleep apnoea, it confers its own independent risk for dementia, said Dr Diego Carvalho, an Assistant Professor of Neurology at the Mayo Clinic Center for Sleep Medicine. That may be because sleep apnoea limits the amount of oxygen that reaches the brain which can increase inflammation in brain and damage blood vessels and cells.
Too Much Sleep
On the other end of the spectrum, too much sleep also appears to be linked to an increased risk of dementia, perhaps more indirectly. If a person is regularly staying more than nine hours in a bed at night or taking multiple naps during the day, it may be a sign that he is sleeping very poorly, which could raise the risk for Alzheimer because of the reasons listed above. Alternately, needing excess sleep might be related to mental or physical disability. Mental health conditions like depression (affective disorder) and physical health condition such as diabetes or cardio-vascular problems are associated with high risk of dementia as are the physical inactivity loneliness and social isolation. At this point, there is no clear causative role of long sleep in relationship to dementia. Dr Carvalho said. It may be more like a symptom of an underlying problem than the cause of the problem.
An Early Spectrum
Some of the first areas in the brain affected by Alzheimer are those that help regulate sleep and circadian rhythms. As a result, the people who develop the condition may experience sleep problems even before they show signs of memory loss or other symptoms. Along with Amyloid, the other main protein to cause Alzheimer’s disease is called Tau. Like Amyloid, Tau also accumulates in the brain ultimately damaging brain cell. One of the first places that Tau built up appears are these brain-stem areas important for regulating sleep and awake cycles, Dr Winner said. So, we think that Tau showing up in these areas early on is going to disrupt peoples’ sleep / wake cycles. Common sleep problems can be a sign of common dementia as well. In lewy-body dementia and Parkinson’s disease, dementia for example a rapid eye movement sleep is sometimes disrupted, causing people to act out their dreams, something your bed partner may notice.
Normally, when you have these rapid eye movements sleep, that is time when the body’s skeletal muscles tone to almost zero (flaccid) so the muscles do not move. In the R.E.M behavior disorder, this suppression of muscle tone is lost and so the muscles actually move the way you as in your dreams. It is normal for elders to sleep a little more or little less after retirement or to wake up or go to bed a little earlier or later than they used to. But if there has been a dramatic shift, consider seeing your doctor.
If somebody is getting up at 2am or 3am or sleeping for three hours during the day that is a cause for concern. If somebody is getting up an hour earlier than they used to and having 30 to 60 minutes’ nap during the day that is much more likely to be just normal ageing.
In conclusion, one must try to sleep optimally i.e., neither too short nor too long. The sleep pattern and duration depend upon varying factors like age, physical health, mental condition, temperature of the surroundings, nature of work & profession etc. As an average, a good sleep of five to seven hours at night and a brief mid-day nap of 20 to 30 minutes (if needed) are healthy and optimal. A good quality sleep makes us a new person who is now able to face the day-to-day challenges of life and career.
