According to some authors, sleep fragmentation and/or intermittent hypoxia occurring in untreated OSA syndrome may influence the HPT axis, reducing Gonadotropin Releasing Hormone (GnRH) secretion, LH pulsatility, and serum total testosterone (12, 13). Twelve studies were found including adult patients with eugonadism or hypogonadism at baseline. The weighted-mean serum total testosterone at baseline was 13.5 ± 7.4 nmol/l, and it was different between the two groups (6.8 ± 3.5 nmol/l in hypogonadal and 15.7 ± 7.0 nmol/l in eugonadal patients). Participants were adult outpatients diagnosed with OSA syndrome; five trials enrolled patients with serum total testosterone 2. The studies were published between 1989 and 2017 and had sample sizes ranging from 5 to 101 patients and a follow-up from 4 to 156 weeks. Lastly, it should be considered that pituitary imaging in patients with serum total testosterone 11). Concerning the latter aspect, it is estimated that CPAP is not able to correct all the nocturnal events in about 20% of patients with OSA syndrome; the risk is increased in patients with concomitant obesity hypoventilation syndrome and chronic obstructive pulmonary disease (54). Of note, only one of them enrolled patients with low serum testosterone (24). It is worth mentioning that untreated severe OSA syndrome contraindicates TRT, due to a time-limited worsening of the sleep disorder (11, 44). It is worth noting that other treatments, such as diet and bariatric surgery, proved to increase total as well as serum free testosterone and SHBG (40). In the present review, no data on serum free testosterone or SHBG in patients with hypogonadism were available. In male patients with obesity, low levels of SHBG are consistently reported. This complex relationship creates a challenging scenario for those affected, as addressing one issue without considering the other may lead to incomplete treatment and suboptimal results. Sleep apnea, a common sleep disorder characterized by repeated interruptions in breathing during sleep, affects millions of people worldwide. TRT may help some men feel more energetic and improve overall well-being, but it doesn’t always fix sleep issues. Many men with Low T report fatigue and insomnia-like symptoms. Low T can disrupt the sleep–wake cycle, leading to difficulty falling asleep, staying asleep, or experiencing restorative deep sleep. Similarly, untreated low testosterone can significantly impact quality of life, affecting everything from mood and energy levels to bone density and cardiovascular health. Addressing both sleep apnea and low testosterone is crucial for overall health and well-being. Avoiding alcohol and sedatives, particularly before bedtime, can also help reduce the severity of sleep apnea symptoms. While TRT can improve many symptoms of low testosterone, it may potentially exacerbate sleep apnea in some cases. In such cases, alternative treatments like positional therapy for sleep apnea may be considered. Fluctuating testosterone levels may also impact on the ventilatory response to hypoxia and hypercapnia, which could explain the higher rates of OSA seen in men on TRT 47,50 (Fig. 2). In addition to lower serum testosterone, patients with severe OSA also have higher levels of general fatigue, physical fatigue and mental fatigue, and reduced physical activity. A mouse study showed that loss of testosterone after gonadectomy results in a significant decrease in the amount of deep sleep, which can be treated by testosterone replacement therapy (TRT) . It is important to understand when and how testosterone is made. When it drops, the whole rhythm of sleep and wakefulness can be disturbed. This shows that testosterone is part of a larger system. When testosterone is low, this balance can be disrupted. Cortisol is a "stress hormone" that usually rises in the morning to help us wake up. It works together with other hormones, such as cortisol and melatonin, to regulate energy and rest. More severe obstruction of the upper airway during sleep results in the obstructive sleep apnea (OSA) or OSA syndrome (OSAS) when there are compatible symptoms present. In some people, though, testosterone replacement therapy can interfere with sleep, especially if it is a high-dose treatment. When low testosterone causes poor sleep, testosterone treatment may improve sleep. At the same time, poor sleep may interfere with normal testosterone production. When testosterone levels are too high or too low, it may impact sleep. Both conditions share symptoms such as tiredness, mood changes, and poor focus. It is important to remember that Low T and sleep disorders often feed into each other. By combining these tests, doctors can see if Low T, a sleep disorder, or both are causing the symptoms. These are not only signs of poor sleep but also signs of hormone imbalance. Men who do not sleep well often show lower levels of testosterone in morning blood tests. During certain stages of sleep, the body releases hormones that restore energy and rebuild tissues. Getting treated can help restore your sleep, your testosterone, your sex drive—and your quality of life. Don’t let untreated sleep apnea quietly rob you of your health, energy, or vitality. Getting screened is easy—Daybreak offers a simple at-home sleep test, so you don’t need to spend a night in a lab or deal with hospital wait times. In fact, leaving sleep apnea untreated can lead to even more serious health consequences down the road.
