What happens physically during times of stress?

The stress response system originally kept people safe from environmental threats like hungry predators. Your body’s modern-day stress response is identical to that of your ancestors, preparing the body for a battle or a quick getaway — the classic fight-or-flight response.

Stress causes a cascade of physical reactions, including:

• An accelerated heartbeat.
• Opening of lung airways to improve oxygen delivery.
• Release of adrenaline to speed you up.
• Release of glucose to power muscles.
• Widened pupils to improve vision.
• Lowered gastrointestinal activity so you can run, not digest.

Today, you rarely face a situation where you truly need to fight or flee. But your body still starts the stress response when there aren’t options for fighting or escaping: a traffic jam, a disagreeable boss or coworker, a looming deadline.

In the modern, sedentary person, these stress responses lead to high blood pressure, diabetes, central body obesity, palpitations, anxiety, and muscle tension and pain.

How does stress affect the heart?

In the movies, people under intense stress sometimes dramatically keel over from a heart attack, but that’s extremely rare. The real danger is the accumulated impact of chronic stress, which contributes to each of the top five risk factors for developing heart disease: abnormal cholesterol levels, diabetes, high blood pressure, obesity and smoking.

How does stress affect the brain?

Chronic stress can make your brain behave in an Alzheimer’s-like manner. Stress adversely affects a key structure in the brain, the hippocampus, leading to impaired memory and problems with orientation and sense of direction.

These brain changes may have evolved to protect against the memory of traumatic and stressful events, like being attacked by a predator; but short-term memory loss hinders today’s brain-intensive lifestyle. We all know the frustration of forgetting where we put our keys, the names of people we just met or other recent events.

How does stress disrupt sleep?

When you’re continually stressed, your body constantly pulses out stress hormones, which make it harder to fall asleep and impairs the deepest stages of sleep. That can lead to hyperarousal insomnia, where your mind and body are easily woken by sounds or by your own stressful thoughts.

What about energy levels?

Chronic stress can make you tired. Your adrenal glands act like battery packs; they provide energy-producing substances such as adrenaline on demand, a key part of the stress response. Unfortunately, many people overuse these limited battery reserves with endless work and personal demands. The result: fatigue.

Does stress make you age faster?

Longstanding stress can cause you to age more quickly than normal. One study links chronic stress to faster aging in otherwise healthy people — but on the bright side, the study also found that mood management and self-control against unhealthy behaviors (such as smoking and overeating) can help reverse these effects.

Bottom line? Keep an eye on how stressed you are and what you can do about it. Your body will thank you.