Sitting down most of your waking hours is as likely to kill you as base jumping, indicate a gaggle of studies released this year that found sitting to be an early marker for heart disease, diabetes, cancers and early death. This makes sitting a lifestyle risk factor along with smoking, overweight, high blood pressure, among others.

Irrespective of how much you exercise the rest of the time, spending a lot of time sittingups your risk of heart disease, diabetes, cancer and dying prematurely, concluded a large review published in the Annals of Internal Medicine this week. It’s not enough to exercise for one hour a day and be sedentary for 23 others, said the study, which found people spend half their day sitting at workstations or hutched over smartphones.

This study echoed the findings of a 2012 review of 18 studies that included 794,577 people, which had found that sitting for long periods raises the risk of diabetes, heart disease and death. The study, published in Diabetologia, the journal of the European Association of the Study of Diabetes, also found that the risk remained even when people met physical activity guidelines.

Trouble ahead

Apart from leading to weight gain, sitting down raises calcification in the heart’s arteries, which is an early marker of heart disease, reported a study at the American College of Cardiology’s 64th Annual Scientific Session in March.

Again, the study found no association between coronary artery calcification – calcium in plaques deposited within the heart’s arteries that cause narrowing and obstruction of blood flow measured through a heart CT scan — and the amount of exercise a person does, suggesting too much sitting cannot be countered by exercising.

Sitting also shows a gender bias. Spending leisure time sitting raises women’s cancer risk by 10 per cent, specifically for multiple myeloma (a type of blood cancer), breast, and ovarian cancers. The risk for women remained after adjusting for physical activity, body weight and other factors.

There was association between sitting time and cancer risk in men, showed the study – published in Cancer Epidemiology, Biomarkers, and Prevention — of more than 146,000 men and women (69,260 men and 77,462 women) who were part of the American Cancer Society Cancer Prevention Study II Nutrition Cohort.

Fix it

An average adult spends 50-70% of their waking hours sitting down, and by limiting the time spent sitting, the risk of diabetes, heart disease and death can be reduced. Breaks in sitting time improve markers of good health, such as lower body weight and improve diabetes control.

Even healthy adults who exercise and sleep for eight hours each night should target to lower sitting time by two to three hours in a 12-hour work day, say experts. Cutting back on sitting time — for example, standing up or moving for one to three minutes every half hour and fidgeting when you can’t — should be a companion strategy to exercising an hour a day to lower risk of disease and death, show studies.

This week, a study in American Journal of Preventive Medicine reports that fidgeting counters the adverse health impacts of sitting for long periods. The study, from the University of Leeds and University College London, found that while women who spent time sitting ranked high on risk levels, those who fidgeted a lot while sitting had the same low risk of disease as active women, showed data from more than 35,000 women aged 35 to 69 in the UK.

Get smart

Targeting sitting time, rather than physical activity, is the most effective way to reduce prolonged sitting, showed another review of strategies designed to reduce sitting time published in the journal Health Psychology Review earlier this week. The research, from King’s College London, searched the current existing literature on interventions that sought to reduce sitting time. Of the 38 interventions assessed, 23 (60 per cent) were found promising whilst 15 (39 per cent) were found to be worthless.

Among things that work are offering employees sit-stand desks at work, keeping a record of individual sitting time, setting individual goals for limiting sitting time, and using prompts and cues on smartphones and fitness gadgets to remind you to get moving.

The take-away for all of us is that prolonged sitting is a risk factor for lifestyle diseases independent of how much you exercise and the sooner you get up and start moving, the healthier you will be.