129 E 90th Street #1W,
New York, NY,

(646) 609-4250

Sleep for Your Health

By Andrea Vannelli


I often find that I’m urging patients to get more sleep and this can be a tough one for some. I can relate. As a young person, I was much more of a night owl, feeling most alert and productive in the later afternoon and into the night. Fortunately, I had a day job with regular hours that kept me pretty well on track, but I habitually scrimped on sleep for various reasons, managing to get through the following day with the help of a little morning caffeine. This is a very common pattern: one in three US adults reports getting less than the recommended minimum of 7 hours. For our busy lifestyles, squeezing an extra hour or two out of the day can feel like a win. Short-changing your sleep may be manageable for the odd occasion or demanding circumstance, but if you are habitually getting fewer than 7-8 hours of sleep per night, you may want to re-think your habits. Let’s look at some reasons why. 


Stages of sleep:

Let’s first review a bit on the structure of sleep. Throughout a typical night’s sleep, we run through four or five cycles (approximately 90 minutes each) that change as we progress through the night. The non-dream state happens first and slows everything down, allowing the parasympathetic NS to dominate. This eventually deepens to a deep or slow-wave stage which is incredibly healing and restorative, and where the brain consolidates memories. The REM or dream state follows, which is crucial for emotional first aid, creativity and assists with memory. As the night progresses, the work of the non-dream state grows more efficient and we spend relatively more time in REM. 


Sleep is not passive:

Sleep is not merely the absence of wakefulness. While we sleep, our bodies are actively working—cleaning, regulating, building and restoring. The brain has a special housecleaning mechanism called the glymphatic system that is only fully activated during the deep sleep or slow wave phases. It clears away debris and accumulations the area associated with inflammatory conditions and diseases such as Alzheimer’s. Deep sleep quality tends to decline with age and can be reduced by caffeine and certain prescription medicines—including most sleep aids.


Sleep impacts your hormones:

Key hormones are produced at night, including those involved in conception. Research shows that over time inadequate sleep may alter reproductive hormones leading to irregular menstrual cycles. In addition, studies clearly show that short sleep has a negative impact on the hormones that regulate our hunger, satiety, insulin and sugar management, resulting in stronger cravings and increased blood glucose levels. This effect is evident after just a single night of inadequate sleep. Over time, chronically disturbed sleep increases the risk of developing Type 2 diabetes. 


When it comes to conception, 7-8 hours seems to be the sweet spot, with more or less sleep being detrimental. Research shows that women getting fewer than 7-8 hours of sleep are 15% less likely to conceive compared with those sleeping 7-8, and that women undergoing IVF are 25% more likely to fall pregnant if their sleep time falls within this window. Men who consistently sleep as little as 4-5 hours have significantly lower levels of testosterone and sperm count. 


Sleep is healing:

Sleep helps us physically heal and recover from illness. Deep sleep recharges the immune system and overhauls the cardiovascular system. Disruption of sleep wave rhythms impairs the function of natural killer cells, and short sleep (6 hours) can temporarily switch off certain genes related to immune function, as well as up-regulate inflammation. Sleep is so important for heath that studies show once a person’s average nightly sleep falls below 7 hours, their risk for all-cause mortality increases.


Sleep is good for your brain:

Sleep enhances memory and is necessary both before and after learning in order to assimilate and solidify new information. Sleep also makes you more creative, improves motor skills and protects you from dementia. The dream state or REM stage of sleep soothes the stress response and is crucial for our emotional well-being. Some experts consider it akin to overnight therapy, helping us mitigate fear-based response, improve judgment and process stimuli. Importantly, the most beneficial stage of REM sleep happens in the last hour of the night.


Timing matters: 

Don’t miss out on the hours before midnight—these are prime for sleep quality. Chinese medicine has understood this concept for centuries, and there are now modern studies to support it. For example, a 2020 study that looked at bedtime and sleep duration in men showed that significantly better levels of semen quality occurred in those with bedtimes prior to 10:30 pm (and lasting 7.5-8 hours in duration). 


Tips for optimizing sleep:

  • Keep a regular sleep schedule. Having a routine is less stressful on the body, and sticking with a regular pattern makes it easier for the body to enter the important deep sleep stages. Keeping a consistent sleep schedule is beneficial for the rhythmic nature of the body’s circadian and reproductive hormones. Spending time outdoors during the day can help sync up circadian rhythm and improve sleep quality. 
  • Get to sleep by 10 pm and allow yourself at least 8 consecutive hours of overnight sleep opportunity. Actual sleep duration may end up being slightly less, so the main objective is to be asleep for a good 7.5 hours.
  • Mind the light. Darkness is necessary to send clear signals to the brain’s pineal gland and inhibits melatonin production. Avoid blue screens after dusk and use blackout curtains if you have a lot of ambient light affecting your bedroom environment. 
  • In addition to being dark, your bedroom should be cool, comfortable and quiet for the best sleep. Keep electronic distractions like cell phones and televisions in another room while you sleep. 
  • Relax your mind. Make a habit of doing calming things in the hours leading up to bed. Avoid raising your stress hormones with activities like intense exercise or exciting television shows. 
  • Limit the stimulants. Caffeine in particular directly interferes with adenosine, the primary neurochemical that promotes sleep. It also delays the onset of melatonin production. Caffeine has a half-life of several hours for the average person. Even if you can fall asleep easily enough, studies show that caffeine reduces the amount of slow-wave sleep, which is the restorative type. 
  • Avoid sleep aids, alcohol and stimulants. In most cases, these interfere with the brain’s natural cycling and can suppress the most restorative parts of sleep. 


Sleep expert and brain scientist Matthew Walker notes that a particularly harmful characteristic among sleep-impaired individuals is that they consistently underestimate how sleep-deprived they are. Does this sound like you? A good way to check this for yourself is to experiment with optimizing your sleep quality and duration for a couple of weeks to see how it feels. 


Why do we procrastinate going to bed at a decent hour? According to the National Sleep Foundation, one reason may be something called an intention behavior gap. This is the idea that we may delay bedtime despite our best intention and awareness because our capacity for self-control is at its lowest late in the day. Coupled with the spillover of unfinished daytime demands, taking time at the end of the day for desired activities can feel like a well-deserved reward. But there can be a price to pay if it cuts into necessary sleep time. 



Beroukhim, G., Esencan, E. & Seifer, D.B. (2022) Impact of sleep patterns upon female neuroendocrinology and reproductive outcomes: a comprehensive review. Reproductive Biology and Endocrinology, 20, 16. https://doi.org/10.1186/s12958-022-00889-3


Hvidt, J. E. M., Knudsen, U. B., Zachariae, R., et al. (2020) Associations of bedtime, sleep duration, and sleep quality with semen quality in males seeking fertility treatment: a preliminary study. Basic and Clinical Andrology, 30, 5. https://doi.org/10.1186/s12610-020-00103-7


Kloss, J. D., Perlis, M. L., Zamzow, J. A., Culnan, E. J., & Gracia, C. R. (2015). Sleep, sleep disturbance, and fertility in women. Sleep medicine reviews22, 78–87. https://doi.org/10.1016/j.smrv.2014.10.005


Lateef, O. M., & Akintubosun, M. O. (2020). Sleep and Reproductive Health. Journal of circadian rhythms18, 1. https://doi.org/10.5334/jcr.190


Walker, M. (2017). Why we sleep: Unlocking the power of sleep and dreams. Scribner.