Science reveals how sleep and exercise affect our stress response in different ways. While both are pillars of health, experts explain which one to prioritize first to restore emotional and physical balance, and why these habits boost each other for a healthier, fuller life.

How Stress Affects Your Body

In a fast-paced world, stress has become a constant companion. But when your body cries for help, what should you do first: rest or move? Science has a clear and hopeful answer on how to balance your physical and mental health.

The Restorative Power of Sleep

Cortisol, known as the stress hormone, follows a natural rhythm: it peaks in the early morning and drops at night. However, lack of sleep disrupts this cycle. According to research from the University of Chicago highlighted by the U.S. Centers for Disease Control and Prevention (CDC), losing even 1 or 2 hours of sleep regularly can raise cortisol levels by up to 60%, weakening the brain circuits that regulate emotions.

The hypothalamic-pituitary-adrenal (HPA) axis is the body's main stress response system. When sleep is disrupted, this axis becomes overactive, making it harder to adapt to daily pressures.

Sleep specialist Dr. Alex Dimitriu warns that sleeping less than 6 or 7 hours significantly increases the risk of chronic diseases. Meanwhile, Imperial College London notes that adequate rest is essential for the brain to consolidate memories, clear metabolic waste, and restore emotional balance.

Exercise as a Stress Release Valve

If sleep is the foundation, exercise is the builder of resilience. The American Psychological Association (APA) states that people who exercise regularly have lower cortisol and adrenaline levels after each session. Movement triggers endorphins and serotonin, key neurotransmitters for fighting anxiety.

An exciting meta-analysis published in March 2026 in the British Journal of Sports Medicine, involving over 79,551 participants, showed that aerobic exercise reduces symptoms of anxiety and depression across all ages. Even the Harvard T.H. Chan School of Public Health calculated that replacing just 15 minutes of sedentary time with intense activity lowers the risk of major depression by 26%.

Which One Comes First?

Though it sounds like a dilemma, experts agree: if you are sleep-deprived, rest wins. Adding intense exercise on an exhausted body can be counterproductive. As Dr. Dimitriu puts it: 'Sleep is always the most important factor. It is the foundation on which everything else rests.'

Once sleep is restored, it's time to move. The Mayo Clinic recommends at least 150 minutes per week of moderate aerobic activity to keep stress in check. The great news is that both habits feed each other: good sleep boosts energy for workouts, and exercise deepens sleep quality.

Source: Infobae (original in Spanish, August 4, 2026)