If you are not so keen on going to the gym and would rather stay in watching TV, being a couch potato may actually help you get in shape. Watching sports on TV or live may improve your fitness by increasing muscle nerve activity and sweat release, according to a recent study.

During aerobic exercise, heart rate and breathing rate typically increase. The rise in heart rate causes an increase in the breathing rate, which allows for the individual to take in more oxygen and transfer it into the blood, according to Montana State University. This process helps stimulate the rise of cardiac output which will allow for more blood to be pumped to the body and muscles.

The shift in autonomic activity causes increases in sympathetic nerve activity in the muscles while engaging in physical fitness. The changes in the cardiovascular system in blood pressure, heart rate, and respiration that occur during exercise are also found to occur in the absence of muscle contraction or movement.

Researchers from the School of Medicine at the University of Western Sydney (UWS), aimed to investigate whether the imagination and observation of exercise produced any significant changes in blood pressure, heart rate, respiration, skin blood flow, sweat release, and muscle sympathetic nerve activity (MSNA) via first person point-of-view. Nine healthy participants — six females and three males — participated in the study. They sat in a reclining comfortable chair in a semi-reclined position with their legs supported horizontally to accurately monitor any significant changes.

Very fine needles were inserted into the outer nerve of the volunteers as a means of recording the electrical signals of nerve fibers directed to the blood vessels. This is considered to be a very sensitive measure of the body’s physiological responses to physical or mental stress, according to the researchers.

The small group watched video of a three-minute walk along the beach, a 16-minute run up a hill, stair climbing, a cliff top run, and a recovery phase involving gazing out over the ocean. The nine participants were initially shown a static image on a computer screen as the researchers monitored their MSNA and other physiological factors.

Their measurements remained stable while watching the unmoving landscape image, but changed when the volunteers were shown the 16-minute video of a runner jogging. The researchers noted that this was the first time MSNA was shown to increase when people watched physical activity.

"Now we have shown that it increases when you are watching a moving scene as if you were running yourself,” Vaughan Macefield, one of the lead researchers and professor of integrative physiology at the School of Medicine at UWS, said in a news release.  

This finding supports the notion that viewing emotionally charged images does indeed increase sympathetic nerve activity and sweat release in viewers. The participants were sitting relaxed with no muscle activity but showed an increase in MSNA implying that he responses were psychogenic — originating from the mind rather than the body.

"Although these changes were small, they were all appropriate physiological responses to exercise," said Rachael Brown, co-author of the study, in the press release.

The researchers do warn that couch potatoes should not be quick to replace sports viewing with regular fitness. The body may get a small workout from being a bystander in a sports event, but engaging in real physical activity is viewed as the best way to maximize the benefits of exercising.

The Centers for Disease Control and Prevention says that adults should partake in at least two hours and 30 minutes of aerobic physical activity at a moderate level or one hour and 15 minutes of aerobic physical activity at a vigorous level each week. Those who opt for five or more hours of physical activity each week will reap more health benefits from exercising.

For simple ways to increase your physical activity, click here.

Source: Brown R, Kemp U and Macefield V. Increases in Muscle Sympathetic Nerve Activity, Heart Rate, Respiration, and Skin Blood Flow During Passive Viewing of Exercise. Frontiers in Autonomic Neuroscience. 2013.