After ingestion, carbs are converted into glucose and burned for fuel or stored as glycogen in the liver and muscles for later use. According to the European Journal of Applied Physiology, each gram of glycogen stored in the muscles holds at least 3 grams of water. The more carbs you eat, the more water you'll hold, which can make your arms look fuller.
And perhaps one of the best new findings about exercise — especially if you, like many people, struggle to find the time to fit it into a busy day — is that all those benefits of physical activity can be had even if you only squeeze in a few minutes of exercise a day. While doctors used to think that we needed to engage in 30 to 60 minutes of exercise a day, new research is finding that we can see benefits with shorter bursts of physical activity. “As little as 15 minutes a day of high-intensity activity that leaves you breathless, like swimming, can kick start your metabolic rate and reduce body fat and increase muscle mass,” says Dr. Berger.
Exercise reduces risks for serious illness. Exercise reduces people's chances of developing and dying of illnesses such as heart disease. It does this by lowering illness risk factors such as triglyceride and overall cholesterol levels, while improving the level of HDL (the "good" cholesterol which is thought to reduce the risk of heart disease). Weight-bearing exercise and strength training activities help to maintain or increase bone mass, reducing a person's risk for osteoarthritis and associated bone fractures. Regular exercise also lowers resting blood pressure rates for hours after an exercise session is over. In addition, moderate exercise may significantly reduce the risk of developing type II diabetes. Arthritics who exercise often experience more strength and flexibility in their affected joints as well as a reduced pain levels. Furthermore, exercise may delay or prevent the development of arthritis in other joints. Regular walking of over a mile a day has been shown to reduce the risk of stroke significantly. Exercise even appears to reduce the risk of developing some cancers, especially cancers of the breast and colon.
A workout once in a blue moon won’t do it, she says: you really have to exercise regularly, since hormone levels largely return to baseline after you exercise. That said, there’s an effect that accrues over time, which is what you want to harness by being active at least a few times a week. “What I’d caution readers is not to view our results as ‘one 20-minute moderate exercise will be a cure for all inflammatory conditions,’” says Hong. “These significant immune effects we observed occurred immediately with one bout of exercise, and likely will occur each time one exercises. So every time you exercise you’d see this effect, which will be cumulative over time.”