UNITED STATES – Many of us regularly wear an activity tracker, which counts the number of steps we take in a day. Based on these numbers, it can be hard to make sense of what they might mean for our overall health. Is it just the overall number of steps in a day that matter or does exercise intensity, such as going for a brisk walk or jog, make a difference?
In a new study, which looks at activity tracker data from 78,500 people, walking at a brisk pace for about 30 minutes a day led to a reduced risk of heart disease, cancer, dementia and death, compared with walking a similar number of steps but at a slower pace. These results were recently published in two papers in the journals Jama Internal Medicine and Jama Neurology.
For these studies, which included participants from UK Biobank, people with an average age of 61 agreed to wear activity trackers for seven full days, including nights, at the beginning of the trial. This study represents the largest to date that incorporates activity tracker data.
“Activity tracker data is going to be better than self-reported data,” said Dr Michael Fredericson, a sports physician at Stanford University who was not involved in the study. “We know that people’s ability to self-report is flawed”, he added, often because people do not accurately remember how much exercise they did in a day or week.
After collecting this data, researchers then tracked participants’ health outcomes, which included whether they developed heart disease, cancer, dementia or died during a period of six to eight years.
Researchers found that every 2,000 more steps a day lowered the risk of premature death, heart disease and cancer by about 10 per cent, up to about 10,000 steps a day. When it came to developing dementia, 9,800 steps a day was associated with a 50 per cent reduced risk, with a risk reduction of 25 per cent starting at about 3,800 steps a day. Above 10,000 steps a day, there were not enough participants with that level of activity to determine whether there were more benefits.
In the past, similar studies have also shown that the benefits of walking start well before the often-touted 10,000 steps a day.
But the researchers of this study did something new. When they looked at the step rate a minute of the highest 30 minutes of activity a day, they found that participants whose average highest pace was a brisk walk (between 80 and 100 steps a minute) had better health outcomes compared with those who walked a similar amount each day but at a slower pace.
Brisk walkers had a 35 per cent lower risk of dying, 25 per cent lower chance of developing heart disease or cancer, and 30 per cent lower risk of developing dementia compared with those whose average pace was slower.
To put these numbers into perspective, a person whose total daily steps include 2,400 to 3,000 that are brisk walking could see a sharp reduction in the risk for developing heart disease, cancer and dementia, even without taking many more steps beyond the total daily number.
“It doesn’t have to be a consecutive 30-minute session,” said University of Sydney research fellow Matthew Ahmadi, one of the authors of the studies. “It can just be in brief bursts here and there throughout the day.”
But the important thing is to aim for walking a little faster than your normal pace. When it comes to the differences between brisk walking and jogging, there was not enough data to determine if one was better than another, and both resulted in better overall health outcomes than at a slower average pace.
Still, a 2013 study followed 49,005 runners and walkers and suggested that brisk walking or jogging similar distances offers similar heart health benefits, although walking takes longer.
This study is part of ongoing research into just how important exercise intensity is to various health outcomes. These latest findings suggest that maintaining good health does not necessarily require a lot of high-intensity exercise and that a regular amount of moderate-intensity exercise, such as brisk walking, can offer a high level of protection against developing conditions such as heart disease, cancer or dementia.
When it comes to incorporating more intense exercise into your daily life, Dr Tamanna Singh, a cardiologist at the Cleveland Clinic, often reminds her patients that everything is relative. “Everybody is starting from a different training status,” she said.
A brisk pace for one person may not be brisk for another, but what matters is the relative effort. At a light exercise intensity, a person can sing a song, while at a moderate intensity, a person can easily carry a conversation, but would struggle to sing. At higher intensities, conversation becomes difficult, if not impossible.
When it comes to brisk walking, “at these moderate levels of effort, you are able to increase your aerobic capacity”, said Dr Singh. Besides the long-term health benefits, such intensity would also lower blood pressure, moderate blood sugar levels and lower the risk for heart attacks and strokes.
The key is to walk at an intensity that is manageable, but also slightly pushes the boundaries of what is a comfortable pace.
“That constant slow stress on your body is what leads to fitness gains,” said Dr Singh. “If you’re just getting started, this is probably the easiest way to get started and stay committed, consistent and injury-free.” NYTIMES