Is exercise really necessary? Can't we just eat better and be healthy?

The short answer is, yes we need exercise not just better eating to attain better health. Here is the long answer of why. 

Our muscles use ATP as their sole source of fuel and ATP is made in the muscle cells by anaerobic respiration. Oxygen determines how much ATP will be made in the muscles so fitness is how much oxygen can be consumed in the muscle cell mitochondria. Regular exercise has a major impact on the ability to be healthy and stay healthy. Regular exercise lowers blood lipids, strengthens and makes the heart bigger, lowers blood pressure, increases the size of the muscle mitochondria for better metabolism, decreases the rate of fatigue, strengthens the bones, and shifts your body composition from fat to lean muscle mass reducing metabolic syndromes. There is no down side to exercise so it must be part of any healthy lifestyle.

Nutritionally, carbohydrates and fats can both be used to make energy and using fat sounds good but carbohydrates are more efficient and better for performance. It takes about 30 minutes of exercise for fat to start supplementing the carbohydrates for energy. Most people aren't running marathons although some do and so I illustrate that we only have 1500 calories of stored carbohydrate energy and if we burn about 100 calories per mile we will run out of carbohydrate fuel after 15 miles and have to utilize our 70,000 calories of stored fat energy. Which is harder and it's called hitting the wall when your body makes the switch. More glucose during the race is needed.

Emotionally, exercise improves mood by releasing endorphins, the feel good neurotransmitters. According to a Mayo Clinic study it also helps improve mood by reducing immune system chemicals that can worsen depression and it elevates body temperature which has a calming effect It also makes you happier throughout the day if you're not as fatigued by each stressor. You feel better if you accomplished something and you did something good for yourself.

Environmentally, you want to exercise where the air is as clean as possible since you will be sucking a lot into your lungs. Also you want to train where you will be competing if you are an athlete. If you are running a race in Denver the oxygen percentage in the air is lower or if you train in New England and then run a race in Texas it's important to realize how your body will react and what alterations you might need to make.

Some religions claim the body is a temple. I think this is a good way to think about the vessel that allows our spirit to inhabit it. Each spirit is on this earth for a limited amount of time in this body. If we respect our spirit we must respect our body. Taking good care of our our spirits' vessel requires proper nutritional fuel and oxygen to make the muscles work. Exercise makes use of the great food we eat and allows us to consume more oxygen, making the vessel strong. It's important to respect our essence, our unique spirits and the body that carries it.