How does physical activity benefit your health?
We’re now using our unique data-driven approach to tackle some of the biggest health challenges we face today, including cancer, heart disease and dementia.
Together with our study contributors, we’ll be investigating how our lives shape our health, immunity and wellbeing based on five interconnected strands of health:
What happens to your body when you’re active?
There are two main types of activity: cardiovascular and resistance (strength). What happens to your body depends on which type you’re doing.
This is anything that raises your heart rate, such as walking, running, swimming, dancing, cycling and sports like football and tennis, or everyday activities like cleaning or gardening.
The main effect of cardiovascular activity is to make your heart beat faster, pumping more blood, oxygen and nutrients to the cells and tissues around your body, particularly the muscles you’re using to move. You’ll also breathe faster during cardiovascular activity to take in more oxygen.
Most types of cardiovascular activity are aerobic — literally “with oxygen”. The oxygen is used to break down sugars and release the energy you need. Depending on the intensity and your fitness, cardiovascular activity can be sustained for long periods, up to many hours.
It is also possible to do short bursts of intense anaerobic activity, such as sprints, where your body burns energy without using oxygen. These have to be followed by periods of recovery, allowing you to literally get your breath back.
Resistance or strength activity
These activities require you to push, pull or hold against something that offers resistance, such as weights, resistance bands, gravity or your own body. Resistance training is more intense than cardiovascular activity and helps to build endurance and muscle strength.
Examples of resistance or strength activities include lifting weights or bodyweight exercises like pushups, yoga and Pilates. You can also build your strength through daily activities like lifting heavy objects at work or home (including your kids!)
When you perform strength exercises, you expose your muscle fibres to stress, creating thousands of tiny tears in your muscles. Whilst this might sound damaging, it’s actually a good thing because it stimulates new muscle growth. As your body repairs the tears, you gradually build stronger and bigger muscles that adapt to meet greater demands, such as lifting heavier weights.
While some activities could be classed as purely cardiovascular or resistance, such as walking versus lifting heavy weights, many provide a mix of both.
Strength is also particularly important as you age. Maintaining strength means daily tasks are more manageable, and we can remain independent for longer. Extra strength also reduces our risk of falls and fractures.
How does physical activity benefit your health?
In general, cardiovascular exercise is great for keeping you fit by improving the function of your heart and lungs. In addition, resistance or strength training builds muscle and boosts your metabolism in the long term. But being physically active has a much broader range of benefits for both mind and body.
We’ve previously written about how the benefits of physical activity for your body, particularly aerobic exercise, range from improving cardiovascular function and reducing blood pressure to regulating your blood sugar levels and building muscle strength.
In the long run, these changes might protect you from ill-health. For example, regular physical activity is associated with a reduced risk of long-term health conditions, including heart disease, diabetes, high blood pressure and cancer.
Regular physical activity could also help to protect you from infectious diseases by boosting your immune system. Regular physical activity has been linked to having more protective antibodies and immune cells and a lower risk of contracting an infectious disease. Studies have even shown that vaccination might stimulate a better immune response when combined with physical activity.
When it comes to mental health, many of us will be familiar with that happy feeling just after a workout. This is thanks to the release of “happy hormones” known as endorphins.
Regular physical activity is associated with significant improvements in stress and depression and overall mental wellbeing. A review of 31 studies found higher physical activity was linked with higher levels of wellbeing and quality of life and lower symptoms of depression, anxiety, and stress.
How much physical activity should you do?
Recommendations vary by country but generally suggest that all adults should do at least some sort of physical activity every day.
In the UK, the NHS recommends doing some strengthening activities at least 2 days per week plus 2.5 hours of moderate-intensity activity such as brisk walking, riding a bike or dancing. Alternatively, you could do 1.25 hours of vigorous-intensity activity like running, mountain biking or swimming each week. There are similar recommendations from the HHS in the US.
When thinking about how much physical activity you do each week, it’s not just about hitting the gym. The most important thing is to find something you enjoy, and that is manageable for you.
Everyday activities like walking, gardening, carrying the shopping and even cleaning all count as physical activity. So do dancing, swimming, martial arts and taking part in sports, from archery to Zumba and everything in between. And there are plenty of tips to help you stay active outdoors and at home if you have limited mobility or other disabilities.
How can we study the connections between activity and health?
Researchers use various methods to study the effects of activity on health.
Perhaps the best-known are clinical trials, which can be used to compare the effects of different types of physical activity. For example, scientists have used clinical trials to look at the effects of physical activity on pain, mobility, cognition, cardiovascular health, diabetes and overall causes of death.
Although clinical trials are the gold standard, they are also difficult to run. Researchers need to randomise people to be more or less physically active and change their lifestyles for an extended time. They then measure changes in outcomes like fitness, muscle strength or heart health.
To get around this, some activity researchers asks participants to self-report their activity and health using questionnaires. But this is less accurate because participants may misremember or overreport their activity levels.
Wearable technology such as movement trackers and smartwatches can record a range of measures in addition to activity, such as heart rate, blood pressure, skin temperature, and oxygen levels.
Our own large-scale study of nutrition and health — PREDICT — uses wearable tools such as activity trackers and blood sugar sensors to get accurate real-time data about the connections between activity and health.
What has ZOE discovered about activity and health?
PREDICT is the world’s biggest in-depth nutritional research program. We’re studying how each person uniquely responds to the food they eat and how this interacts with their overall health and lifestyle, including levels of physical activity.
Already, we’re beginning to gain new insights into the effect of physical activity on health. For example, early analysis of our data suggests that being physically active after a meal can improve blood sugar control.
We found that people in our high activity group, who were active for more than 80 minutes of the 2 hours following a meal, had blood sugar levels on average 35% lower than those in the low activity group, who were active for less than 40 minutes of the 2 hours.
On average, people in the medium activity group also had 18% lower blood sugar levels than those in the low activity group.
This has important implications for broader health. For example, people with diabetes struggle to control their blood sugar levels, and poor blood sugar control is associated with a higher risk of heart disease.
Researchers have also found that people with good blood sugar control are more likely to have better outcomes from COVID-19. And our own ZOE Health Study revealed some interesting findings about activity during the pandemic.
We found that during lockdown in the UK, around a quarter of people increased their physical activity, while another quarter did less. In the US, a slightly greater proportion of people reduced their physical activity (36%), while 24% became more active.
The biggest increases in activity were seen in people who were less active before the pandemic. People who already had high levels of physical activity coming into the pandemic tended to maintain this during lockdown.
ZOE’s Head of Programs Emily Leeming states that "a 2019 meta-analysis found that it's both physical activity and reduced sedentary behaviour that matter. Even light-intensity physical activity like a brisk walk is a great start. If you spend a lot of your day sitting or lying down - try and get up and move for a minute every hour."
What do we still need to find out about activity and health?
Despite all the progress made in recent years, there are still plenty of unanswered questions about the connections between physical activity and our health, immunity and wellbeing.
For example, scientists need to do more work to understand how regular physical activity can help with appetite and weight control. It seems that a high level of physical activity can help protect against weight gain, and some suggest this may be linked to better appetite control.
We also need to understand the effects of weight-bearing exercise and how this interacts with nutrition to improve bone and muscle health with age. This is important because, as a population, we are getting older and living longer, so maintaining our physical function can result in improved quality of life in older age.
ZOE’s large-scale, data-driven approach offers a powerful way to find answers to these questions and more, not just for diet but across all five strands of health.
The ZOE Health Study aims to connect each of our personal health journeys to patterns in the wider population. This will reveal new insights into health and disease that could help us all lead healthier, happier lives.
Together, we’re changing the future of health research. To get involved, simply download the ZOE Health app, fill in your health profile and get in the habit of logging daily reports. We’ll be adding new studies and research activities as we bring them online, so watch this space for updates.
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Explore the ZOE Health Academy to learn more about the science of nutrition, healthy living, and immunity.