Summary: The best kind of exercise for stress reduction might not be what you expect: a new study compares five approaches to exercise to determine what works best to reduce stress and psychological distress.
Key Points:
- Studies show elevated stress and psychological distress are associated with levels of circulating cortisol in the body.
- Research shows dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis is the primary cause of elevated cortisol associated with stress and psychological distress.
- People with anxiety disorders, depressive disorders, and chronic stress show HPA dysregulation resulting in high cortisol levels.
Stress and Mental Health
Most of us understand that stress can have a negative impact on mental health. Some stress can be good – most of us know this, too. Stress can cause us to work harder and prepare more thoroughly for upcoming events. Stress can heighten our senses and give us the extra edge we need in a crisis or an emergency, whether physical or psychological.
However, chronic exposure to the stress hormone, cortisol, can cause long-term physical and emotional problems. In this article, we’ll focus on the psychological problems it can cause, specifically psychological distress and generalized stress, and learn about the best kind of exercise for stress reduction, determined by the extent to which various types of exercise reduce levels of circulating cortisol.
We’ll share and discuss data from a study published recently by the National Institutes of Health (NIH) from the journal “Sports” called “The Optimal Exercise Modality and Dose for Cortisol Reduction in Psychological Distress: A Systematic Review and Network Meta-Analysis.” The study authors/designers identified this goal for their work:
“This systematic review and network meta-analysis assessed the relative efficacy of different exercise modalities and the optimal dose in modulating cortisol levels in adults with psychological distress.”
The research team defines psychological distress as follows:
“Psychological distress refers to the negative emotional responses elicited by exposure to stressors, with anxiety, depression, and stress being its core manifestations.”
They also share the following top line, worldwide estimates on recent trends in mental health:
“The Global Burden of Disease study in 2021 reported that the age-standardized incidence rate of mental disorders increased by 15.2% from 1990 to 2021.”
And summarize the rationale for assessing the role of exercise in stress reduction:
“Exercise is increasingly recognized as a non-pharmacologic strategy for stress regulation…Exercise intervention…provides a noninvasive alternative that may lower costs while conferring additional benefits for both physical and mental health.”
Let’s take a look at the study.
The Best Exercise for Stress Reduction: Intense, Easy, or Something Else?
Spoiler alert: the answer is something else – but we won’t give it away just yet.
To assess the evidence on the best kind of exercise for stress reduction, by way of efficiency in cortisol reduction, the research team examined 44 studies with data from 3,284 participants with psychological distress.
Here are the details about the studies included in the analysis:
- 20 studies assessed the impact of yoga on cortisol
- 14 studies assessed the impact of aerobic exercise on cortisol
- 10 studies assessed the impact of mixed types of exercise on cortisol
Researchers excluded studies that combined therapy and medication with exercise, as well as reviews, case studies, editorials, and studies with incomplete or insufficient data for analysis. Among the 44 studies that met their stringent selection criteria, the average length and manner of intervention followed this pattern:
- 12 weeks long
- 3 exercise sessions per week
- 55 minutes per exercise session
With valid and appropriate studies identified, the research team divided the exercise interventions into five categories:
- Yoga
- Continuous aerobic exercise (CAR)
- Multicomponent exercise (MCE), i.e. combined aerobic and resistance components
- Qigong
- High-intensity interval training (HIIT)
Before we share the results, we’ll define/explain the important details for each of these five categories.
The Contenders: Best Exercise for Stress Reduction
We’ll take them one at a time, in the order established above:
Yoga
Yoga is a traditional practice that incorporates mind-body practice that integrates physical movements and fixed postures with breathing techniques, relaxation, and targeted concentration. Common benefits of yoga include increased strength, flexibility, physical control, concentration, and relaxation. Yoga styles assessed in these studies included a typical mix of postures, breathing, and relaxation. In other words, this study didn’t look at hot yoga (done in room @ 85°- 95° Fahrenheit) or kundalini yoga (meditation/energy focused).
Continuous Aerobic Exercise (CAE)
Continuous aerobic exercise means walking, jogging/running, swimming, or bicycle riding for at least 20 minutes at a time. CAE assessed in this study all fell in the moderate range of intensity.
Multicomponent Exercise
Multicomponent exercise combines multiple types of activity to achieve optimal results. Typical multicomponent exercise includes a combination of resistance training, i.e. weights, and aerobic exercise, i.e. jogging/running. Currently, both CrossFit and Orange Theory are popular approaches to multicomponent exercise.
QiGong
QiGong is a traditional Chinese physical system that combines easy, flowing circular movements with specific breathing patterns and guided, focused concentration. Evidence shows qigong improves joint health, increases relaxation, and promotes overall psychological wellbeing. Styles of QiGong assessed in this study included QiGong for health and Tai chi.
High-intensity Interval Training (HIIT)
High-intensity interval training (HIIT) involves performing short, intense intervals of activity separated by short recovery window to maximize time at intensity without exhausting muscles too quickly. Evidence shows HIIT yields significant improvements to cardiovascular performance in a short period of time.
To establish a dose-response curve, i.e. [x] amount of exercise required for [y] amount of cortisol reduction – researchers used a standard called metabolic equivalents (METs) per week, determined by a equation including frequency and duration. We’ll report one set of data using METs, and a second set of in a slightly simplified manner, sharing instead the minimum and optimal minutes per week needed for each type of exercise to reduce cortisol and thereby reduce psychological distress.
Let’s take a look at what they found.
Outcomes: What Type Worked Best?
First, we’ll list the best kind of exercise for stress reduction, in order of efficiency and effectiveness, as defined by the dose-response curve, i.e., the type of exercise that reduces cortisol – and by extension, stress – the most quickly and in the least amount of time.
Best Exercise for Stress Reduction: Time and Effectiveness
- Yoga: 630 METs per week minimum to achieve peak cortisol reduction
- Qigong: 530 METs per week to achieve peak cortisol reduction
- Multicomponent exercise: 1200 METs per week to achieve peak cortisol reduction
- Continuous aerobic exercise: 770 METs per week to achieve peak cortisol reduction
- High intensity interval training (HIIT): showed reduction at lower doses, but produced a negative response at higher doses, negating its statistical significance for cortisol reduction in the context of stress/psychological distress reduction
The results show clearly that yoga is both the most efficient and most effective way to reduce levels of circulating cortisol and thereby reduce levels of stress and psychological distress. For some, this may seem counter-intuitive: a common opinion is that that the more intense the workout, the more pronounced the stress reduction.
These results turn that notion upside down, showing that increasing high intensity training increases cortisol past specific duration threshold. In contrast, yoga reduces cortisol quickly and does not increase cortisol, while Qigong reduces cortisol slowly, with reductions increasing over time. In fact, at the 12-week point in the studies examined, cortisol reductions associated with Qigong were still increasing, implying that over the long-term, Qigong may possibly yield superior results compared to yoga.
Next, we’ll share a helpful set of information the researchers created that lists amount of time required each week to experience the most significant reductions in cortisol – and reductions in psychological distress – for each type of exercise.
Best Exercise for Stress Reduction: Recommended Time Per Week
- Yoga:
- Minimum/optimal minutes per week: 80/270
- Breakdown of sessions per week:
- Min: 4 sessions @ 20 min
- Optimal: 4 sessions @ 70 min
- QiGong:
- Minimum/optimal minutes per week: 150/150+
- Breakdown of sessions per week:
- Min: 4 sessions @ 20 min
- Optimal: 4 sessions @ 70 min
- MEC:
- Moderate:
- Minimum/optimal minutes per week: 120/120
- Breakdown of sessions per week:
- Min: 4 sessions @ 30 min
- Optimal: 6 sessions @ 20 min
- Vigorous:
- Minimum/optimal minutes per week: 90/90
- Breakdown of sessions per week:
- Min: 3 sessions @ 30 min
- Optimal: 6 sessions @ 15
- Moderate:
What we find interesting – and quite surprising – is that it’s possible to experience significant cortisol reduction with four (4) sessions of yoga at twenty (20) minutes each. What may be more interesting is that yoga at that level is superior to three (3) sessions of vigorous mixed exercise lasting thirty (30) minutes per session.
That’s excellent information to have and can help anyone interested in using exercise to reduce stress. But the researchers didn’t stop there: they made the results even easier to understand and apply to daily life.
Stress Reduction Simplified: Amount of Exercise You Need by Level of Intensity
This is the final set of data from the study. This information shows the minimum and optimal times required to reduce cortisol levels, by general level of intensity: low, moderate, or vigorous.
General Exercise Prescription: Best Exercise for Stress Reduction
- Low intensity exercise
- Minimum/optimal minutes per week: 90/180
- Breakdown of sessions per week:
- Min: 3×30 or 4×45
- Optimal: 6×15 or 6×30
- Moderate intensity exercise:
- Minimum/optimal minutes per week: 60/120
- Breakdown of sessions per week:
- Min: 3×20 or 4×30
- Optimal: 6×15 or 6×20
- Vigorous exercise
- Minimum/optimal minutes per week: 45/90
- Breakdown of sessions per week:
- Min: 3×15 or 3×30
- Optimal: 5×10 or 6×15
Here’s how the study authors characterize their results:
“In summary, our results suggest that yoga and qigong exert favorable effects on cortisol regulation even at moderate or higher doses, whereas HIIT and aerobic exercise demonstrate dose-sensitive responses, with excessive loads potentially detrimental…These results highlight the importance of tailoring exercise prescriptions to individual stress regulation capacities and physiological adaptations in populations with psychological distress.”
That’s the surprise we hinted at in our introductory summary: the least intense/vigorous interventions yielded the greatest reductions in cortisol the most quickly, while the most intense/vigorous interventions were slower to reduce cortisol, and – in the case of HIIT – result in an increase in levels of cortisol.
However, it’s important to understand that the long-term, overall health benefits of exercise modalities like HIIT can improve mental health and general wellbeing: the data here reveals that the mechanism is not directly related to cortisol reduction.
To learn more about the impact of exercise on mental health, please read the following articles on our blog:
Gianna Melendez
Jodie Dahl, CpHT