Chronic versus acute increases (or decreases) in "bad" things should be a topic of discussion. All too often we hear certain buzz-words or phrases that end up sounding detrimental to our health. This can fall under the category of hearing something repeated so many times that it then becomes "fact." It turns out, however, that increasing something acutely (short-term) can be beneficial for the body to more readily manage it over the long-term. Here is a really quick list of health factors off the top of my head that can be beneficial over time:
Heart Rate - long-term heightened resting heart rate is generally considered to be bad. Short-term spikes in heart rate (exercise) can actually lower resting heart rate over a longer period of time.
Blood Pressure - similar to heart rate, chronic heightened blood pressure can be deleterious to overall health, whereas temporarily raising blood pressure due to stimulus like resistance training can improve the overall health of the cardiovascular system.
Blood Sugar - Increased blood sugar following intense exercise can benefit recovery efforts of the muscles, however long-term heightened blood sugar can be detrimental to overall health.
Reactive Oxygen Species - These are natural by-products of metabolism. They have gotten a bad rap recently which has caused a spike in interest in "anti-oxidants." Sure, chronic inflammation caused by reactive oxygen species can be bad, however, acute bouts can be beneficial in the stimulation of growth and repair due to exercise.
Vitamin C and E are quite often used as anti-oxidants. Supplementing with them may hinder your performance gains, however. Take this recent study, for example:
Vitamin C and E supplementation blunts increases in total lean body mass in elderly men after strength training.
The aim of this study was to investigate the effects of vitamin C and E supplementation on changes in muscle mass (lean mass and muscle thickness) and strength during 12 weeks of strength training in elderly men. Thirty-four elderly males (60-81 years) were randomized to either an antioxidant group (500 mg of vitamin C and 117.5 mg vitamin E before and after training) or a placebo group following the same strength training program (three sessions per week). Body composition was assessed with dual-energy X-ray absorptiometry and muscle thickness by ultrasound imaging. Muscle strength was measured as one-repetition maximum (1RM). Total lean mass increased by 3.9% (95% confidence intervals: 3.0, 5.2) and 1.4% (0, 5.4) in the placebo and antioxidant groups, respectively, revealing larger gains in the placebo group (P = 0.04). Similarly, the thickness of m. rectus femoris increased more in the placebo group [16.2% (12.8, 24.1)] than in the antioxidant group [10.9% (9.8, 13.5); P = 0.01]. Increases of lean mass in trunk and arms, and muscle thickness of elbow flexors, did not differ significantly between groups. With no group differences, 1RM improved in the range of 15-21% (P < 0.001). In conclusion, high-dosage vitamin C and E supplementation blunted certain muscular adaptations to strength training in elderly men.
Oftentimes I see individuals take a product or supplement because they hear it is good for them. Vitamin C and E supplementation (above study) are 2 supplements that many folks take simply because they feel as though, "some is good, more must be better!"
Well, according to this study out of Norway, too much anti-oxidant supplementation blunted some muscular adaptations from strength training. Here is another example of something that you may not want to supplement with, unless you have been told you are deficient in some particular category.