(NEWS) 3 nights of sleep deprivation & heart risk: Study shows changes in biomarkers – What the research says

Sleep is far more than just rest – it's a biological necessity for your heart. But how quickly does sleep deprivation really harm your body? A new study from 2025 delivers alarming results: Just three nights with only 4.25 hours of sleep are enough to drastically alter your molecular profile.

Researchers have found that 25 key cardiovascular biomarkers deteriorate significantly – even in young, healthy men. What's particularly insidious is that exercise cannot fully counteract these negative effects. What does this mean specifically for your long-term heart risk, and how can you effectively protect yourself?

What the study shows

In a randomized crossover study, scientists investigated the effects of acute sleep deprivation on heart health. Sixteen healthy men with an average age of 23 spent several nights under controlled conditions in a sleep laboratory.

The participants went through two phases: In one phase, they slept a normal 8.5 hours for three nights, and in the other phase, their sleep was reduced to only 4.25 hours for three nights.

Using the advanced Olink CVDII panel, the researchers analyzed 88 specific proteins in the blood that are considered indicators of cardiovascular health. The results were clear and statistically significant.

• After just 3 nights, 25 cardiovascular biomarkers were significantly altered.

• The risk profile shifted in a direction otherwise associated with heart disease.

• The statistical probability (p-value) for this relationship was 0.006.

• The proteins most affected were those that control inflammatory processes.

• The changes occurred independently of other lifestyle factors.

• Even young, healthy bodies showed these stress-related reactions immediately.

Mechanism: How does sleep deprivation affect the cardiovascular system?

The mechanism behind these changes is complex and primarily affects the immune system and circadian rhythms. Sleep deprivation puts the body into a state of alarm, triggering inflammatory cascades.

Particularly striking was the upregulation of pro-inflammatory cytokines. These messenger substances signal stress to the body and can damage blood vessels and promote plaque formation in the long term.

• IL-27 increase: An interleukin that plays a role in chronic inflammation.

• LGALS9 (Galectin-9): Has been significantly upregulated and is associated with heart failure.

• Chemokines: These signaling proteins attract immune cells and promote vascular inflammation.

• Circadian disruption: 33% of proteins fluctuated unnaturally strongly during sleep deprivation (vs. 18% during normal sleep).

• Stress axis: The hormonal regulation of hunger and stress becomes disrupted.

Exercise cannot compensate for a lack of sleep.

Many people believe they can "sweat out" a short night's sleep with an intense workout the next morning. However, the study shows that this is a misconception. While exercise generally has positive effects, the foundation of sleep is irreplaceable.

The researchers had the subjects exercise and measured the reaction of the so-called "exerkines" – messenger substances such as IL-6 and BDNF, which are normally released through exercise and have a health-promoting effect.

• Exercise did increase the levels of IL-6 and BDNF.

• However, this positive increase was significantly weaker under sleep deprivation.

• The body's regenerative response to training was muted.

• Negative inflammatory markers remained elevated despite exercise.

• The cardiovascular risk profile did not fully normalize through training.

• Training while overtired could expose the body to additional stressors.

For whom is sufficient sleep particularly important?

The results are relevant to almost everyone, but certain groups are at particularly high risk. If you belong to one of these groups, you should make your sleep hygiene a top priority.

Since biomarkers change after just three days, the classic "weekend deficit" or the stressful deadline week is already problematic for your heart.

• Shift workers: Due to the constant changes, their risk is chronically increased.

• Students: Studying through the night for exams has measurable physiological costs.

• Young parents: Interrupted sleep quickly accumulates into a risk factor.

• Managers & High Performers: Those who view sleep as a weakness pay with their heart health.

• Athletes: Regeneration and supercompensation take place during sleep – without sleep, there is no progress.

Practical recommendations for better sleep

The good news is: sleep is a modifiable risk factor. You have the power to improve your health by giving your sleep the attention it deserves.

It's not just about duration, but also about quality and consistency. Try to integrate the following evidence-based tips into your daily routine.

• Prioritize 7-9 hours: Make sleep a non-negotiable appointment in your calendar.

• Consistency is key: Go to bed and get up at the same time every day.

• Light hygiene: Avoid blue light (screens) 60-90 minutes before going to bed.

• Cool environment: A bedroom at 16-18 degrees promotes deep sleep.

• Avoid heavy meals: Eat your last large meal 3 hours before going to bed.

• Caffeine limit: Do not drink coffee after 2 pm, as caffeine has a long half-life.

Limitations of the study

As with any scientific work, there are limitations we must consider to properly interpret the results. Transparency is crucial in science.

• Small sample size: With 16 participants, the group is relatively small.

• Men only: The study examined only young men; effects in women may differ.

• Short duration: Acute effects were studied (3 nights); long-term effects were not measured.

• Homogeneous group: The participants were healthy and young; effects could be stronger in cases of pre-existing conditions.

• Biomarkers vs. endpoints: Markers in the blood were measured, not actual heart attacks (surrogate parameters).

⚠ Important note:

This information is for general informational purposes only and does not constitute medical advice. It is in no way a substitute for professional advice or treatment from qualified and licensed physicians. If you are experiencing sleep problems or heart conditions, please consult a specialist.

Sources:

• Brandão LEM, Zhang L, et al. The overlooked trio: sleep duration, sampling time and physical exercise alter levels of olink-assessed blood biomarkers of cardiovascular risk. Biomarker Research . 2025;13:52. DOI: 10.1186/s40364-025-00776-0

• Lloyd-Jones DM, Allen NB, Anderson CAM, et al. Life's Essential 8: Updating and Enhancing the American Heart Association's Construct of Cardiovascular Health. Circulation . 2022;146(5):e18-e43. DOI: 10.1161/CIR.0000000000001078

• Wang YH, Wang J, Chen SH, et al. Association of Longitudinal Patterns of Habitual Sleep Duration With Risk of Cardiovascular Events and All-Cause Mortality. JAMA Netw Open . 2020;3(5):e205246. DOI: 10.1001/jamanetworkopen.2020.5246