Curious how testosterone impacts your energy and sleep?

This applies to both men and women!

This month, I'll explore testosterone and sleep. This all started with a friend of mine, 40 years old, telling me he had started testosterone therapy to “get through the week”. This really surprised me. You’re exhausted, and the solution is... Testosterone?

Clearly, I wanted to learn more about this! Especially given that many people are generally not sleeping well. And clinics are popping up everywhere, selling men on testosterone treatment with slogans such as "Are you tired?".

Many men have probably wondered whether their testosterone impacts, say, their muscle development or their sex life, but now they can learn how it impacts their sleep. Although testosterone is primarily associated with men, this topic is also relevant for my female readers. 

So, whoever you are, read on! 

Want a spoiler? Testosterone treatment appears to not be the silver bullet for better sleep – and can come with significant risks.

Testosterone: A brief recap

Testosterone is a steroid hormone, found in humans and animals. Testosterone is an androgen: a male sex hormone. Yet, it is also found in women. Let’s start with what it does in both men and women.

Testosterone in men

In men, it’s mostly produced in the testicles, with small quantities produced in the adrenal glands.

What does it do? 

Testosterone is crucial in muscle and bone mass and red blood cell production. Higher levels of testosterone are also associated with increased sexual drive, maintaining erectile function, and sperm production.

How does it change across a lifetime?

As with any hormone, testosterone changes throughout our lifetime. In males, peak production levels are observed during puberty. Late teens to early twenties mark the peak levels of testosterone—this serves the reproductive function. With age a gradual decline is observed: around 1-2% per year, often starting around 30-40 years.

Too high or too low levels

What are "normal" levels?

The American Urological Association considers 450 – 600 ng/dl (equal to 15.6 – 20.8 nmol/l) the normal range.

Low

Normal ageing is associated with a decline in testosterone, but there is also a clinical syndrome called “hypogonadism,” which is caused by a lack of androgens or their action. This means you either have low testosterone or your testosterone isn’t working properly (because it is, for instance, converted into estrogen).

Hypogonadism is not a single disease, but a collection of different conditions, often diagnosed in inconsistent ways. This obviously hurts our ability to study it properly.

Low testosterone (below 230 ng/dl or 8nmol/l) is associated with lower sexual desire and function, reduced erectile functioning, loss of bodily hair, depression, an increase in fat tissue, infertility, and fatigue. It’s also associated with decreased muscle mass and lower bone density.

As there is no strict line between hypogonadism and “normal ageing”, there is a tricky grey area, characterized by low-ish testosterone levels (230 – 346 ng/dl or 8 –12 nmol/l). In these cases, when clear symptoms are present, testosterone treatment could be trialed. But check out the "testosterone trap" below.

It’s important to address hypogonadism as it's believed to potentially increase the risk for cardiovascular and all-cause mortality, in addition to insulin resistance and diabetes. But with such a heterogeneous syndrome, it's honestly hard to say at this point whether it's the low testosterone itself creating risks.

High

That said, there are also risks to high testosterone. Health-wise, high levels of testosterone are associated with high blood pressure, lower levels of “good” cholesterol (HDL), and increased risk for prostate cancer and hypertension. Risky and aggressive behavior is also linked to high testosterone. And, of course, high testosterone can have a significant side-effect, which I will dive into later: insomnia.

Testosterone in women

In women, testosterone is produced in various locations, with one quarter in the ovaries, one in the adrenal gland and the other half in the peripheral tissues (e.g., in fat and skin cells). Women have much lower levels: about 5-10% of what men produce.

What does it do? 

Despite testosterone being primarily associated with masculinity, it still plays a vital role for women’s sexual, hormonal and bone health, muscle maintenance, and overall well-being. 

In women, testosterone is recognised for its role in enhancing female libido and genital sensitivity, which is associated with sexual satisfaction. Some recent studies show that testosterone may even influence mate choice and improve sexual function in postmenopausal women.

How does it change across a lifetime?

A similar peak is observed in females around puberty, as testosterone is needed for muscle, bones, and the growth of pubic hair. Compared to men, testosterone levels remain relatively stable during early adulthood and the reproductive period. However, things change a bit during menopause, as testosterone declines, albeit more steadily than estrogen and progesterone. Similarly to men, age-related decline of testosterone affects sexual function in women. 

If you want to read more about sleep and menopause, check out my previous newsletter. 

Too high or too low levels: 

High testosterone is also problematic for women as it may lead to acne, an increase in bodily hair, irregular or absence of menstrual periods, and polycystic ovary syndrome (PCOS). Meanwhile, as in men, low levels are associated with decreased libido, muscle mass and bone density. 

We should all care about maintaining the right testosterone levels, as this is vital for overall health and well-being.

Testosterone release across 24 hours

Testosterone levels fluctuate throughout the day. Those fluctuations are dependent on and influenced by various factors, such as sleep, stress, and the body’s internal biological clock.

Peak testosterone levels occur during the early morning hours (often around 8am). The figure above shows testosterone levels in young (23-31 years) and older men (48-80 years).

Testosterone: A pulsatile, ultradian rhythm

Testosterone concentration oscillates approximately every 9 minutes (burst-like secretory patterns). The hypothalamus controls this rhythm - a brain region crucial for hormone regulation. This pulsatile release pattern is crucial for the proper functioning and release of testosterone, ensuring that muscle growth, mood, and sexual functioning are efficiently regulated throughout the day. 

Sleep’s impact on testosterone

Sleep is the foundation of many things in our lives, including hormones and specifically testosterone. In a healthy situation, i.e., when we are getting enough sleep, we experience both the circadian and ultradian pulsatile rhythms. 

But what happens if we don’t get good sleep (both in terms of quality and quantity)?

In short, bad sleep has a clear effect on testosterone production – an effect that can be a lot stronger than the standard annual testosterone decline due to ageing!

Sleep loss/fragmentation

Sleep quality and duration significantly affect testosterone levels. However, the majority of these studies are done on men, so unfortunately, it’s hard to say much about testosterone and sleep in women (this needs to change, obviously!). 

One often-quoted study found that getting less than 5 hours of sleep per night for a week reduced testosterone levels in young men by 10-15%. This is quite a bit, considering that normal, ageing-related declines in testosterone are around 1-2% per year. 

Two review papers concluded that both 24 hours and 40-48 hours of continued wakefulness (skipping 1 or 2 nights) indeed lower testosterone. However, partial sleep deprivation (a reduced sleep period of around 4-5 hours) only significantly affects serum testosterone levels when it occurs in the first half of the night.

Moreover, a cross-sectional study on older men showed that testosterone levels increased with increasing sleep duration (up to 9.9 hours). However, an inverted U-shape was observed, as beyond 9.9 hours, testosterone levels started decreasing.

Poor sleep quality

Poor sleep can also disturb the circadian release patterns, leading to reduced testosterone production. Sleep disorders such as sleep apnea have also been found to disrupt healthy testosterone rhythms: lower morning testosterone is observed in men with sleep apnea. There is a question of whether it’s obesity driving some of these effects.

Women: Clinical findings in women are a bit more limited, due to hormonal fluctuations during different life stages - making this topic much more difficult to study. There are, however, modest correlations between increased awakenings and lower testosterone levels. These increased wakefulness periods can disturb our sleep and, in turn, lead to worse testosterone (but also an array of other issues resulting from insufficient sleep quality).

Sleep apnea treatment's impact on testosterone

Men: The research on whether continuous positive airway pressure (CPAP) treatment can be effective in restoring normal testosterone levels for those who suffer from sleep apnea is inconsistent. That said, it's always wise to treat sleep apnea, for a multitude of other reasons.

Testosterone’s impact on sleep

Too high 

High levels of testosterone caused by treatment can lead to sleep issues for men (more on this under treatment). Women with high testosterone levels may be at a higher risk for PCOS, which can lead to problems with sleeping. 

Too low

Having low levels of testosterone can have negative effects on our sleep (especially for men), as it may lead to difficulties with both falling and staying asleep, similar to insomnia. This is what my friend was experiencing as well before he started treatment, lying awake for almost 2 hours each evening before falling asleep.

Testosterone treatment’s impact on sleep

Men

In hypogonadism, a year of testosterone treatment has been shown to lead to significant decreases in fatigue. Sleep wasn’t measured directly, so we don’t know whether this was because it decreased insomnia, improved sleep quality or reduced fatigued through another mechanism. 

Testosterone Replacement Treatment (TRT) can also cause sleep problems though, especially when testosterone levels get too high. Several studies have shown that high doses of synthetic testosterone, as often used in TRT, may lead to poor sleep quality and increase the risk of sleep apnea (sometimes only temporarily though). 

One study in older males showed that testosterone injections reduced total sleep time by about 1 hour, worsened sleep apnea, and increased the duration of sleep-related hypoxemia (abnormally low oxygen blood levels during sleep).

Women

TRT is also used for women, however, usually with just one-tenth of the dose for men. The main benefits following the treatment include increased sexual desire, yet no changes in sleep, bone health, mood, or energy are observed.

TRT: don't rush into it

Marketers urge men to seek testosterone treatments. However, it may not be the solution to your insomnia, tiredness, or fatigue. It’s wise to rule out the other possible causes of fatigue, low sex drive, and other symptoms attributable to low testosterone before starting treatment. 

TRT isn’t something to think lightly of. If you are seriously considering it, I recommend reading this Harvard Medical School newsletter, which highlights concerns and things to consider. 

When testosterone levels are below the normal range (tested in the morning between 7-10 am), make sure to repeat the test another morning before starting TRT – especially as most men stay on it indefinitely. 

In addition, a complete evaluation of hypogonadism is critical (including checks of other hormones, such as gonadotropin). My friend also had a full check and his cause for low testosterone was found to be previous trauma to the testicles from contact sports (American Football).

The testosterone trap

Once men get started on TRT they feel better, but then it's hard to stop it given that while on TRT, the body stops producing testosterone. Most men feel a big difference when they stop because their body's testosterone production has not yet recovered.

Take away: Clearly, there is a bidirectional relationship between sleep and hormone levels: not getting enough sleep can impact testosterone levels, but testosterone levels can also impact our sleep.

Ways to boost your testosterone levels without medication.

TIP 1: Better sleep! 

• Considering sleep loss impacts testosterone, make sure you are not building up a sleep debt.
• Make sure you remain consistent with your schedule, and take advantage of recovery and sleep banking to reduce your chances of accumulating sleep debt! Check out my previous newsletters on those topics ;) 

TIP 2: Exercise

Differences exist regarding the type of exercise and its intensity and again, we definitely need more research to get specific. But here are some pointers: 

• Resistance training (e.g. lifting weights) has been proven to increase testosterone levels in the short term. 
• Combining resistance training with lower body multi-joint movement (such as squats) may lead to optimal increases in acute serum testosterone concentrations. 
• High-intensity training (HIIT) can also be beneficial in boosting testosterone levels.
• Overall, research points to the fact that increasing physical activity boosts testosterone levels, so the more exercise we do - the better!  
• For some people, intense exercise late at night can lead to sleep disruptions. So, check if you need to move your exercise to an earlier time of day if your sleep is suffering. 

TIP 3: Food

The saying “you are what you eat” also applies to testosterone!

• A nutritious and balanced diet with enough protein, fat, and carbohydrates can aid your testosterone levels.
• On the flip side, overeating or constant dieting (not well-balanced and low in fat) may decrease your testosterone levels (especially for men).
• Reducing our chances of accumulating unnecessary fat is crucial. Fat cells produce aromatase (an enzyme responsible for the conversion of androgens to estrogen) and the more aromatase we have, the more testosterone gets converted into estrogen, thereby decreasing testosterone levels.
• However, having too little body fat is not good either, as research shows that there is a negative correlation between testosterone levels and total body fat. However, having more lean mass is associated with greater testosterone levels, so we should strive to eat well and maintain a healthy weight to ensure our testosterone levels are intact.
• Eating processed foods (e.g. fried or highly processed) was also associated with decreased testosterone levels.

TIP 4: Avoid alcohol

• Research clearly shows that excessive alcohol consumption reduces testosterone levels, with studies showing that drinking more than 8 drinks per week increases the risk of testosterone deficiency. 
• Occasional alcohol consumption seems not to affect testosterone levels negatively. However, even in healthy men, testosterone levels were observed to decrease within the first 30 minutes of alcohol consumption. 
• Moreover, alcohol consumption is known to impact erectile function. Testosterone deficiency limits nitric oxide production, which is the key molecule that relaxes the blood vessels in the penis. 
• Of course, alcohol also (independently) deteriorates your sleep quality and has negative effects on your overall health. More on alcohol and sleep in my previous newsletter. 

To get 3 extra TESTOSTERONE TIPS, make sure you subscribe to my newsletter here!

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Next month I will into sleep's role in mental resilience!

Until then, I wish you great sleep!

Dr. Els van der Helm