Eight hours of sleep and still exhausted: sleep apnea often goes undetected for years
He came in about his blood pressure, not his fatigue
A 46-year-old man comes to the clinic. The reason for the visit is high blood pressure. He does not mention fatigue, because in his view it is not a problem. It has been part of everyday life for years.
Asked in more detail, the picture fills in. His wife sleeps in another room because the snoring is loud. She has also noticed that his breathing stops at times and then restarts with a gasp. He wakes a couple of times a night to use the bathroom. In the morning his mouth is dry and his head aches for the first hour. In the afternoon meeting his eyes start to close. On long drives he opens the window and turns up the radio.
At the visit his blood pressure is elevated and his waist circumference has grown over the past few years.
Every one of these symptoms belongs to the clinical picture of sleep apnea. Snoring occurs in between 70 and 95 percent of patients with sleep apnea, witnessed breathing pauses in about 75 percent, dry mouth in 74 percent, morning headache in roughly one in five, increased nighttime urination in about one in four, and difficulty concentrating in nearly 80 percent. [1]
Still, the most typical feature of this case is not any single symptom. The most typical feature is the patient’s own interpretation: I am just tired, work is demanding. The Finnish national clinical guideline says this outright. Recognizing fatigue is difficult for the patient, because the symptom has developed gradually and he attributes it to things like a heavy workload, work stress or shift work. [1]
The patient case is fictional and assembled from typical features. It does not describe an individual patient.
What happens in sleep apnea
When a person falls asleep, the muscles supporting the upper airway relax. If the airway is structurally narrow, it collapses partially or completely during sleep. Breathing stops for at least ten seconds, blood oxygen saturation falls, and the pause usually ends in a brief arousal that the sleeper does not remember. [1]
There can be dozens of these arousals per hour. Sleep is normal in length but broken in structure. That is why the fatigue does not resolve by sleeping longer, and why a person can be tired for years without understanding why.
Two out of three patients with sleep apnea are overweight or obese. One third, however, are of normal weight, and in their case the background is often the structure of the face, jaws or bite. [1] Sleep apnea is most common between the ages of 40 and 65. [1]
At least 4 percent of men and 2 percent of women have symptomatic sleep apnea. According to more recent population studies, moderate or severe sleep apnea is present in 17 percent of middle-aged men and 9 percent of women. In large Finnish registry datasets, sleep apnea has been recorded in between 3.7 and 4.2 percent. [1] The gap between population studies and registries is what makes this a prevention topic. The guideline’s central message is precisely that sleep apnea should be identified and treated earlier than it currently is, particularly in young adults and the middle-aged. [1]
What happens if it goes untreated
The first years are symptom years. Daytime sleepiness, difficulty concentrating, memory problems and mood symptoms are very common in patients with sleep apnea. [1] These are exactly the symptoms that are easily read as work stress, ageing or depression.
Then the vascular system enters the picture. Untreated sleep apnea syndrome increases sympathetic nervous system activity and the risk of cardiovascular disease. [1] Sleep apnea can as much as triple the incidence of hypertension, and more than a quarter of people with hypertension have sleep apnea. [1] [2]
Repeated oxygen deficit is thought to raise the risk of cardiovascular disease and type 2 diabetes through mechanisms including sympathetic activation, impaired endothelial function, low-grade systemic inflammation and increased blood coagulability. [1] Snoring and sleep apnea can increase the risk of developing type 2 diabetes in middle-aged people. [1] [3]
In severe disease the stakes are high. Untreated severe sleep apnea increases the risk of death, particularly cardiovascular death, by between 3 and 6 times.
At this point it is important to say something that is rarely said about sleep apnea. Untreated mild and moderate sleep apnea, where the apnea-hypopnea index stays below 30, does not significantly increase all-cause mortality or cardiovascular mortality. [1] [4] So this is not a matter of every snorer being in mortal danger. It is a matter of who is already heading toward severe disease, and whose symptoms are already costing them their quality of life.
And one risk does not wait years. Untreated sleep apnea syndrome appears to increase the risk of being involved in a traffic accident regardless of whether the patient feels tired. [1] In a systematic review and meta-analysis of commercial drivers, the accident risk ratio associated with sleep apnea most likely fell between 1.21 and 4.89. [5]
The window: when this can still be stopped
Sleep apnea does not begin on the night a partner first notices a breathing pause. It develops over years, and for much of that time it is still reversible. Three things.
Measure. Start with the STOP-Bang questionnaire, which was designed precisely to estimate the pretest probability of sleep apnea. [1] [6] If the score is elevated, book an appointment with a doctor. Before further investigations it is worth checking at least a complete blood count, HbA1c, serum lipids, TSH and an ECG, because something else may lie behind the fatigue. [1] The diagnosis is confirmed by a sleep recording, nowadays most often as home cardiorespiratory polygraphy. [1]
The most effective lifestyle change: weight. Weight management and lifestyle counselling are always part of treatment for an overweight patient with sleep apnea, and in mild sleep apnea weight loss can be sufficient treatment on its own. [1] Lifestyle interventions reduce the severity of sleep apnea, and this rests on the strongest grade of evidence. [7]
In a Finnish randomized trial, an average weight loss of 10.7 kilograms over one year of follow-up significantly reduced the likelihood of having mild sleep apnea. [8] This is an unusually concrete figure: the point is not that symptoms eased, but that the diagnosis itself can disappear.
The most surprising factor: compression stockings. Wearing compression stockings during waking hours apparently reduces the severity of sleep apnea, because they reduce the shift of fluid from the legs to the neck area when lying down. [9] The same fluid mechanism explains why sleep apnea often worsens with sedentary work and with legs that have swollen by evening.
Two further surprises from the same list. Exercise and other lifestyle interventions relieve the symptoms of sleep apnea even when weight does not change. [1] And alcohol before bed relaxes the upper airway muscles enough that the number and duration of breathing pauses can increase. Total alcohol consumption itself appears to raise the risk of sleep apnea, at least in men. [1]
Going deeper
Hypoxic burden, not just the AHI. The apnea-hypopnea index counts events but not their depth or duration. Hypoxic burden captures both the frequency of oxygen desaturations and the duration and depth of the oxygen deficit, and it appears to predict mortality and cardiovascular risk. [10, 11]
REM sleep. The apnea-hypopnea index during REM sleep appears to be associated with greater comorbidity. [12] From this follows a practical point that often goes unsaid: a CPAP device or a mandibular advancement device should be used through the whole night rather than only the first part of it, because REM sleep is concentrated in the early morning hours. [1]
A smart ring does not rule out sleep apnea. Overnight pulse oximetry alone cannot rule out obstructive sleep apnea, and there is a separate Choosing Wisely recommendation on the use of pulse oximetry in sleep apnea screening. [13, 14] A normal oxygen saturation reading on a smart device is therefore not an exclusionary finding. It can certainly raise suspicion, and in that case it has done its job.
Insomnia does not rule out sleep apnea. Between 30 and 50 percent of patients with sleep apnea have concurrent insomnia symptoms. [15] If sleeping pills do not help, the reason may be that the problem was never insomnia in the first place.
Summary
Sleep apnea is a condition where the window is exceptionally long and exceptionally often missed. Symptoms develop over years, they are explained away by work and age, and the diagnosis often arrives only once blood pressure is already elevated. In mild disease the treatment can be weight loss alone. In severe disease the stakes are the heart and the blood vessels.
If you recognized yourself or someone close to you in this, start with the STOP-Bang questionnaire and take the result to a doctor.
See also: the patient version of the Finnish national clinical guideline, Do you have sleep apnea without knowing it? [16]
Sources:
[1] Uniapnea (obstruktiivinen uniapnea aikuisilla). Käypä hoito -suositus. Suomalaisen Lääkäriseuran Duodecimin, Suomen Keuhkolääkäriyhdistyksen ja Suomen Unitutkimusseura ry:n asettama työryhmä. Julkaistu 21.1.2026. https://www.kaypahoito.fi/hoi50088
[2] Uniapnea ja kohonnut verenpaine. Käypä hoito, lisätietoaineisto. https://www.kaypahoito.fi/nix01534
[3] Uniapnea, kuorsaus ja tyypin 2 diabetes. Käypä hoito, lisätietoaineisto. https://www.kaypahoito.fi/nix01537
[4] Lievä ja keskivaikea hoitamaton uniapnea (AHI alle 30) ei lisää merkitsevästi kokonaiskuolleisuutta eikä kardiovaskulaarikuolleisuutta. Käypä hoito, näytönastekatsaus A. https://www.kaypahoito.fi/nak08897
[5] Tregear S, Reston J, Schoelles K, Phillips B. Obstructive sleep apnea and risk of motor vehicle crash: systematic review and meta-analysis. J Clin Sleep Med 2009;5(6):573-581. https://doi.org/10.5664/jcsm.27662
[6] STOP-Bang-kysely, suomenkielinen lomake. http://www.stopbang.ca/translation/pdf/finnish.pdf
[7] Elintapahoidot lieventävät uniapnean vaikeusastetta. Käypä hoito, näytönastekatsaus A. https://www.kaypahoito.fi/nak07297
[8] Tuomilehto HPI, Seppä JM, Partinen MM ym. Lifestyle intervention with weight reduction: first-line treatment in mild obstructive sleep apnea. Am J Respir Crit Care Med 2009;179(4):320-327. https://doi.org/10.1164/rccm.200805-669OC
[9] Kompressiosukkahoito ilmeisesti lieventää uniapnean vaikeusastetta. Käypä hoito, näytönastekatsaus B. https://www.kaypahoito.fi/nak09725
[10] Uniapneapotilaiden happivajekuorman ennustearvo. Käypä hoito, lisätietoaineisto. https://www.kaypahoito.fi/nix03109
[11] Azarbarzin A, Sands SA, Stone KL ym. The hypoxic burden of sleep apnoea predicts cardiovascular disease-related mortality: the Osteoporotic Fractures in Men Study and the Sleep Heart Health Study. Eur Heart J 2019;40(14):1149-1157. https://pubmed.ncbi.nlm.nih.gov/30376054/
[12] REM-unenaikaisen apnea-hypopneaindeksin yhteys uniapnean oheissairastavuuteen. Käypä hoito, lisätietoaineisto. https://www.kaypahoito.fi/nix03108
[13] Koko yön kestävällä pulssioksimetrirekisteröinnillä ei voida sulkea pois obstruktiivista uniapneaa. Käypä hoito, näytönastekatsaus C. https://www.kaypahoito.fi/nak07274
[14] Pulssioksimetrin käyttö uniapnean seulontadiagnostiikassa. Käypä hoito, Vältä viisaasti -suositus. https://www.kaypahoito.fi/dnd00047
[15] COMISA, samanaikainen unettomuushäiriö ja diagnosoitu uniapnea. Käypä hoito, lisätietoaineisto. https://www.kaypahoito.fi/nix03116
[16] Sairastatko tietämättäsi uniapneaa? (obstruktiivinen uniapnea). Käypä hoito -suosituksen potilasversio. https://www.kaypahoito.fi/khp00097
