Flow Neuroscience

July 16, 2025

We’re often told exercise helps prevent depression, but how much is actually enough to make a difference? New evidence suggests the threshold might be surprisingly low.

A groundbreaking study led by Dr Samuel B Harvey, involving nearly 34,000 adults tracked over 11 years, provides a clear answer:

“Only one hour of physical activity per week could reduce the risk of becoming depressed by 12%.” – Dr Samuel B Harvey, University of New South Wales

Why Is Just One Hour Effective?

The key lies in consistency rather than intensity. Just an hour spread throughout the week, such as a few short walks or a single longer session, appears sufficient to stimulate mood-lifting brain changes, reduce inflammation, and trigger endorphin release. Unlike medication or therapy, which can take weeks to start working, exercise often provides immediate mood improvements, building a protective buffer over time.

What Does One Hour of Exercise Look Like?

Here are practical ways to easily incorporate this evidence-based recommendation into your weekly routine:

  • Busy Schedule: 20-minute walks on Monday, Wednesday, and Friday.
  • Weekend-Focused: A leisurely 60-minute bike ride every Sunday.
  • Office-friendly: Four brisk 15-minute walking breaks throughout your week.

All these routines meet the beneficial one-hour threshold, making prevention realistic and achievable.

Is Moderate Intensity Necessary?

To gain the mental health benefits outlined by the research, moderate-intensity exercise is ideal. Moderate intensity means:

  • Feeling warm but not exhausted.
  • Slight breathlessness, yet still able to comfortably talk.

Jogging, cycling, swimming, or brisk walking are all perfect examples. The goal isn’t to push yourself excessively, but rather to maintain steady movement that elevates your heart rate moderately.

What if I'm Already Depressed?

For people experiencing active depression, the recommended exercise dose increases slightly:

  • 30–45 minutes of moderate-intensity exercise, 3–4 times weekly

Regular exercise at this level has been shown to be as effective as psychotherapy or antidepressant medication.

Key Takeaways

  • Minimal commitment, significant benefit: Just one hour per week is associated with a substantial reduction in depression risk.
  • Consistency matters more than intensity: Small, manageable routines create lasting mental health improvements.
  • Flexible routine: Tailor exercise to fit your lifestyle.

Want to explore the full science behind exercise and depression? Read our comprehensive guide here.