To live longer, replace one hour of sitting with walking daily

Why taller people face greater risk of cancer, by researchers

WHEN it comes to staying healthy, the advice is endless – drink more water, exercise more, take your vitamins, eat oily fish, drink more coffee, drink less coffee. But a new study appears to simplify the key to long-term health; it suggests that by replacing one hour of sitting each day with walking, we can decrease our chance of early death by 12 to 14 per cent.

The study, published in the International Journal of Behavioral Nutrition and Physical Activity, was conducted by researchers at the University of Sydney in Australia and included over 200,000 adults who were middle-aged or older.

According to the Centers for Disease Control and Prevention (CDC), adults need at least 150 minutes of moderate-intensity aerobic activity – such as brisk walking – every week, as well as muscle-strengthening activities on two or more days each week.

Although 150 minutes may seem like a lot of time, doing it in 10-minute increments over the course of the week counts, too.

Prof. Emmanuel Stamatakis, lead study author, notes that previous studies “established the benefits of adequate physical activity or sleep and the risks of too much sitting, but this is the first to look at what happens when we replace one activity with an equal amount of another.”

He and his team point to work hours, which account for over 50% of total waking time, adding that “workers in many professions spend on average more than 70 per cent of their work time sitting.”

Meanwhile, the taller one is, the greater the likelihood of developing cancer, according to a new study presented at the 54th Annual European Society for Paediatric Endocrinology Meeting in Barcelona, Spain.

The team, from the Karolinska Institutet and University of Stockholm, both in Sweden, followed 5.5 million Swedish men and women between the years 1958 and 2011, or from the age of 20 up until 2011.

Dr. Emelie Benyi, a PhD student at Karolinska Institutet who led the study, believes this is the first time the association between height and cancer has been studied in men and women on such a large scale, although a link between height and cancer development has been found in other studies.

All the participants were born between 1938 and 1991 and their adult heights ranged from 100-225 cm.

The information about adult heights was collected from the Swedish Medical Birth, the Swedish Conscription, and the Swedish Passport Registers. The cancer data was retrieved from the Swedish Cancer Register.

The team found that for every additional 10 cm of height, the risk of developing cancer increased by 18 per cent in women and 11 per cent in men.

Additionally, taller women had a 20 per cent greater risk of developing breast cancer, while the risk of developing melanoma increased by approximately 30 per cent per 10 cm of height in both men and women.

Sedentary activity, physical activity and sleep are all part of a 24-hour day, but the researchers say previous investigations have largely examined each behavior “without considering what time-dependent behaviors are being displaced.” Their latest study focuses on the effects of replacing the behaviors and compares this with health outcomes in general, including mortality.

To conduct their research, the team used statistical modeling of health data from study subjects who took part in the 45 and Up Study, which spanned a 4-year period.

The team found that swapping just one hour of sitting each day with standing results in a five per cent decrease in risk of early death. Additionally, for those who were not getting enough sleep, swapping just 1 hour of sitting with sleeping each day resulted in a six per cent decrease in risk of early death.

Interestingly, when one hour of walking or exercising each day was replaced with sitting or some other sedentary behavior, the team found a 13 to 17 per cent increase in early death risk.

“The results show that inactivity is an even bigger health challenge than we initially thought,” notes Prof. Stamatakis, adding:

“With the average person sitting watching 2-3 hours of TV a day, there is definitely scope for people to get off the couch and be more active.

But it’s also time for governments to realize that physical activity cannot be treated as the sole responsibility of individuals because we live in a physical activity-hostile world. Finger-pointing at people because they do not do the right thing has not solved any health problem to date, and it is not going to solve the problem of inactivity either.”

Given that there are only 24 hours in a day, he and his team say their research shows we must be scrupulous in how we choose to spend our time.
Standing is a ‘straightforward intervention’

Although the study’s strength lies in its large, population-based sample size, it does have some limitations. For example, the study variables were analyzed through a self-administered questionnaire, which does leave room for some bias and error, including over-reporting of physical activity or under-reporting of sitting time, “due to social desirability bias.”