The Harvard Doctor Who Says We've Been Wrong About Stress This Whole Time

Stress has gotten a bad reputation. We’re constantly told to avoid it, manage it, or eliminate it entirely. But what if we’ve been thinking about stress all wrong?

Sharon Horesh Bergquist, M.D., a Yale- and Harvard-trained physician with nearly three decades of experience in preventive care and healthy aging, is here to set the record straight.

In her book The Stress Paradox, she unpacks the latest science showing that certain types of stress—when applied strategically—can sharpen the mind, strengthen the body, and even slow the aging process.

In our conversation on the mindbodygreen podcast, Bergquist explains the difference between harmful, chronic stress and beneficial, adaptive stress—and how we can harness the latter to improve our health at a cellular level.

The difference between good & bad stress

Not all stress is created equal. Bad stress is chronic and overwhelming—exactly the kind of stress that dominates modern life. It leads to systemic inflammation, mitochondrial dysfunction, and a host of chronic diseases. 

Good stress, on the other hand, is brief, intermittent, and followed by recovery. This type of stress, known as hormetic stress, can actually make us more resilient.

The key? We need to build resilience to bad stress by strategically exposing ourselves to good stressors, such as exercise, temperature extremes, and certain plant compounds.

Exercise as a good stressor

Exercise is one of the most powerful forms of good stress. But it has to be the right kind of stress.

If you’re short on time, a little vigorous movement can go a long way. One study found that just 1-2 minutes of intense activity three times a day—like running up the stairs—reduces all-cause mortality by 40%.

How phytochemicals strengthen cells

Plants face stress in their environment—harsh weather, predators, pathogens. To survive, they produce phytochemicals, which enhance their resilience. When we consume these compounds, we inherit their stress-fighting benefits.

Some of the most well-studied phytochemicals include:

Large-scale studies, including the Global Burden of Disease Study2, have shown that the biggest dietary risk factor for chronic disease isn’t what we eat too much of—it’s what we don’t eat enough of. Prioritizing nutrient-dense, phytochemical-rich foods can have profound longevity benefits.

Bergquist’s go-to sources? Wild berries, leafy greens, coffee, and tea.

Hot & cold therapy: Stressing the body for better health

Another powerful way to incorporate beneficial stress into daily life is through thermal exposure—cold plunges and sauna sessions.

Cold exposure

Cold exposure activates brown fat, which burns energy to generate heat, ultimately improving metabolic health. It also leads to a significant increase in norepinephrine by 530% and dopamine by 250%, boosting mood, focus, and motivation.

For optimal benefits, aim for water temperatures between 50-60°F and gradually build up from 30 seconds to three to five minutes.

Heat exposure

On the other hand, heat exposure raises heart rate in a way that mimics moderate exercise while also stimulating shear stress on blood vessels. This process triggers nitric oxide production, which helps protect against cardiovascular disease. 

Additionally, sauna use has been shown to prevent protein clumping in the brain, a factor linked to neurodegenerative diseases like Alzheimer’s. Experts recommend about 57 minutes of sauna use per week, divided into multiple sessions.

Why too much comfort is harmful

Bergquist emphasizes the importance of stepping away from constant comfort and embracing challenges—physically, mentally, and emotionally. The healthiest people find themselves in a balanced middle ground, a concept known as the Goldilocks principle of stress.

Both extremes—too much stress and none at all—can be detrimental, while moderate, controlled stress fosters resilience. 

This ties into the "use it or lose it" effect, where a lack of challenge leads to physical and mental decline. Our bodies and brains are built to adapt, but only if we give them a reason to.

Over time, our comfort zone either expands or contracts based on how much we push ourselves. The more we embrace discomfort, the more capable we become; the less we do, the more fragile we grow.

The takeaway

Instead of fearing stress, we should harness it. Strategic exposure to good stressors—exercise, fasting, thermal stress, and phytochemicals—can make us stronger, sharper, and more resilient to the chronic stressors we actually want to avoid.

Follow these 4 steps to embrace the power of good stress today:

In the end, stress isn’t the enemy—it’s the key to a healthier, longer life.