Why do muscles burn during exercise?
For a given workload, blood flow to muscles can be increased by increasing heart rate or stroke volume. However, there is a limit to how much blood can be delivered to working muscles. At this point, the only way to supply more oxygen and fuel for energy production is by increasing the surface area of blood vessels.
The body accomplishes this by creating new capillaries that branch off existing ones. This increases muscle’s ability to get nutrients and remove waste products during exercise (and at rest).
The downside of having all these extra blood vessels running through your muscle tissue is that it makes the muscle very “fluffy” looking (this is called “muscle bulk”). Even though you are getting twice as much blood flow through each vessel, there are so many more of them now that overall blood flow may not be increased much at all.
Increased muscle bulk can also hurt speed and endurance since it absorbs a lot of the energy expended during muscle contraction to stretch the tissue.
There is one more reason why muscles burn during exercise. For muscles to contract, there has to be a build-up of calcium ions around the active site of myosin. This increase in calcium concentration can also be achieved by increasing hydrogen ion concentration (acid).
A high concentration of hydrogen ions means low pH, making muscles burn. As previously thought, the burning sensation that you feel when exercising is not coming from fat or lactic acid breakdown. It is simply because your body cannot keep up with how much acid is being produced at any given moment.
Does burning mean muscle growth??
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From the above discussion, it is clear that burning does not mean muscle growth. If you feel like your muscles are on fire during exercise, this sensation usually means that they aren’t getting any more blood flow.
This, in turn, means that there is also no increase in the delivery of oxygen and nutrients to your muscles. Without these elements, your body cannot make energy for movement and thus will not be able to contract with as much force (which has been indicated by the “burn.”). No fuel? No contraction!
Remember that when you work out, you’re trying to tear down your muscles (by increasing the acidity), so they can rebuild themselves bigger and stronger when you rest. If your muscles don’t have enough fuel and oxygen to rebuild, then you’re just working in vain.
If your goal is to increase muscle bulk or burn fat, there are ways around this problem. The easiest way would be to stay within the “fat-burning zone” of exercise intensity. The idea behind this concept is that the lower the exercise intensity level (in other words, less weight lifted), the more it will rely on fat for fuel instead of glycogen (the stored form of glucose in your muscles).
If your main goal is to lose weight or decrease body fat percentage, make sure you include cardiovascular exercises in your workout routine to burn up all that extra fat!
How to sate this jealousy?
Lift weights! As long as you stay within the proper (moderate) weight lifting zone, your muscles will receive adequate nutrients and oxygen supply for growth. If you want, include some cardiovascular exercises in there too, but do not neglect your muscles, or they won’t grow! And if that’s what you wish to do, keep reading this blog to learn how to maximize your workout routine (and reduce gym time).
If you’re an athlete looking to gain strength and size, you must eat enough calories each day (I recommend at least 3000 kcals daily – please see How Many Calories Should You Eat?). Also, drink plenty of water before, during, and after workouts to prevent muscle cramps.
Proteins are the building blocks of muscles, and you need lots of them to recover and rebuild muscle tissue that is torn apart during workouts.
Do not forget carbohydrates! Carbohydrates provide the body with energy for exercise, just like amino acids! So if your goal is to improve athletic performance, get enough carbs so that your muscles won’t be fatigued too soon. Also, make sure you get at least 1 gram of protein per pound of body weight each day so that your muscles will have materials to repair their tissues with after a workout.
How Many Calories Should we Eat?
I recommend taking around 13-15 calories per pound of body weight to maintain a good weight. In other words, if you weigh 168 pounds, you should be eating about 2250-2640 calories daily on average (not including exercise).
If your goal is to lose weight or decrease body fat percentage, reduce your caloric intake by about 10%. This might seem like a lot but remember that every gram of stored glycogen holds 3 grams of water.
So as you burn up those carbs for energy during workouts and the day, make sure to drink plenty of water! If you don’t want to bother with this calculation, take my rule of thumb: 13-15 calories per pound of body weight for maintenance and 10% less if you’re going to lose weight. This will work for any of the goals presented here.