According to a study published in the Journal of the National Cancer Institute, which looked at more than 4 million individuals and 68,936 cancer cases, sitting for long periods of time increases your risk for colon, endometrial and, possibly, lung cancer. The study found that even in physically active individuals, sitting increased the risk, and the risk worsened with each two hour increase in sitting time.
Separate research links long-term sedentary habits with breast and colon cancer.
A study published in the American Journal of Epidemiology found that men and women who sat more than six hours a day died earlier than their counterparts who limited sitting time to 3 hours a day or less. The study surveyed 53,440 men and 69,776 women who were healthy at the start of the study and over the course of the 14-year follow-up they saw a higher rate of mortality among the frequent sitters. “Associations were strongest for cardiovascular disease mortality. The time spent sitting was independently associated with total mortality, regardless of physical activity level,” the study says.
It’s widely known that exercise and a healthy diet are two major factors in maintaining a healthy weight, but there is a third important factor for weight control, according to researchers at the Mayo Clinic—moving throughout the day. In a study on weight gain and loss, where every aspect of diet and exercise was controlled in a lab, the researchers added 1,000 calories to all of the subjects daily diets. None of the people were permitted to exercise, but some people in the study were able to maintain their weight, while others gained weight. The researchers couldn’t understand why some were able to avoid gaining weight without exercise. How did they keep from gaining weight? Those who maintained their weight did so by unintentionally moving more throughout the day.
Sitting for extended periods effects blood sugar levels and insulin in the body, meaning not only are sedentary people more likely to be obese, but they are also more likely to develop type 2 diabetes. An article published in Diabetologia examined the results of 18 studies with nearly 800,000 participants and determined that those who sat the most were twice as likely to develop type 2 diabetes as the individuals who sat least.
Muscles are healthiest when they are being used and challenged on a regular basis, so it’s not surprising that staying seated for eight or nine hours a day might bring some negative repercussions. Muscles are pliable but when locked in sitting position for the majority of the day, everyday, they do get stiff. After years of constantly sitting the body is used to sitting and not as proficient at running, jumping or even standing. Researchers believe this might be part of the reason elderly people have such a hard time getting around later in life.
LPL or lipoprotein lipase is an enzyme that breaks down fat and uses it as energy, when the enzyme isn’t working as it should, that fat is stored. In a study published in The Journal of Physiology, mice were tested for LPL levels in three states—laying down for most of the day, standing for most of the day and exercising. LDL activity in the laying mice was very low, levels rose more than 10 times when the mice simply stood but exercise had no additional effects on the LDL levels in the mice’s legs. The researchers expect the results to carry over in humans too. The larger point is that people can’t combat the effects of sitting with a half hour or hour of exercise alone—standing throughout the day is the answer.
With hours and hours of sitting associated with higher sickness and mortality rates, who wouldn’t be depressed? The news is both terrifying and disheartening, but knowing about the risks isn’t the reason frequent sitters are more often depressed. Researchers say since sitting reduces circulation it’s harder for “feel-good hormones” to make their way to receptors. A study published in the American Journal of Preventative Medicine followed 9,000 middle-aged women and determined that those who sat longer and did not meet minimum exercise requirements suffered from depression at much higher rates compared with the women who sat less and exercised more. When it came to sitting, those who sat for more than seven hours a day were 47 percent more likely to suffer from depression than those who sat four hours or fewer.
On the exercise front, women who didn’t exercise at all had a 99 percent higher risk of developing depression than those who met minimum exercise requirements. Researchers concluded physical activity could alleviate depression symptoms and likely prevent future symptoms.