Aerobic training has many negative health effects, and being as more than 45,000 people ran the New York City Marathon on Sunday, this topic is more important than ever. Aerobic training stresses the adrenals, chronically raises cortisol, may lower testosterone, may hinder reproduction, can shrink reproductive organs, causes oxidative stress, and results in persistent inflammation. It lowers peak power output, makes you slower, and leads to a catabolic state in the body if you perform it regularly without any resistance training.
Research scientists and athletic coaches have begun to express concern about the negative health effects of aerobic training, particularly for aerobic endurance athletes who put themselves under high daily physiological stress for prolonged periods. In fact, they’ve started to look for strategies to minimize the many negatives of aerobic training, and luckily there are some things that work! Adding strength training to an aerobic program, practicing martial arts, and supplementing with specific antioxidants and nutrients can actually do wonders to counteract the negatives of aerobic exercise.
Of course, it would be easier to just stop the aerobic exercise and substitute it with strength and anaerobic system training for better results and fewer negative health effects. But, since doctors and health professionals continue to recommend aerobic exercise, and even Apolo Ohno has taken up endurance running and competed in the New York City Marathon, this trend towards aerobic exercise doesn’t seem to be diminishing. And there are still some common misconceptions about aerobic exercise, as you can see by reading the comments to my recent article, The (Many) Negative Effects of Aerobic Training
, about why aerobic training is bad.
In this article, I will address the confusing aspects of the negatives of aerobic training, and provide some simple things aerobic endurance trainees can do to minimize the negative health effects and improve performance. Coaches and trainers who work with elite aerobic athletes should take note because these are research-proven ways to better performance and wellness for your athletes.
Short Review of the Bad News About Aerobic Training
Long-term aerobic training, both at an elite level and at a recreational intensity, has been shown to lead to chronic inflammation and elevated cortisol. Chronic inflammation is bad because it results in premature aging of tissues and has been linked to heart disease, diabetes, and cancer. For the recreational population that may perform anywhere from 20 to 45 minutes of aerobic training a few days a week, aerobic training typically leads to elevated cortisol, lower androgen hormones, increased inflammation, and does little to help with fat or weight loss. “The effect of regular aerobic exercise on body fat is negligible,” writes researcher Stephen H. Boutcher in his article “High-Intensity Intermittent Exercise and Fat Loss.” ?
Aerobic training doesn’t help with fat loss because it creates a hormonal environment that degrades muscle, spikes cortisol, and even though you’re burning calories, the deficit is rarely enough to offset the catabolic hormonal environment. Plus, if you’re doing aerobic training on exercise machines, you may suffer from lower insulin sensitivity from exposure to “dirty electricity” or the electromagnetic frequency bands that are generated by cardio machines and other forms of electrical power.
The situation is slightly different for elite or long distance aerobic endurance athletes. Research shows they suffer from an even greater catabolic hormonal state with significantly high cortisol levels from the intense physiological stress of training. They also have lower testosterone and androgens. High cortisol and exposure to inflammatory biomarkers has researchers and coaches concerned about the residual health effects for endurance athletes and they have started to look for ways to counter the negatives.
Body Fat and Elite Aerobic Athletes
Elite aerobic athletes do
tend to have lower body fat compared to the rest of the population, but research shows that anaerobic athletes such as sprinters have even lower body fat than long distance runners. This is because they have more muscle, which helps burn fat, and because they do sprints that also burn fat. Also, studies show endurance athletes who perform strength training as part of the program have lower body fat than those who don’t.
Benefits of Aerobic Training for Sedentary People
There are some benefits of aerobic exercise for sedentary people and specific populations, but there are also negatives that can be avoided if you just choose a different mode of exercise—strength and anaerobic system training. The key here is that it is
better to do aerobic training than to do absolutely nothing and be sedentary
. So, if you only have two options, of being sedentary and not moving, or doing 30 minutes of aerobic training, by all means, do the aerobic training. But, you’ll get better results if you do strength training instead, or in addition to the aerobic training.
To review, the bad news about aerobic training is that it doesn’t help the everyday person lose fat; it elevates cortisol, lowers androgens, degrades muscle, lowers power, and increases inflammation if done for a prolonged period. Now for the good news!
Take Antioxidants to Reduce Inflammation and Oxidative Stress
Get as many antioxidants in your diet as possible to fight inflammation and oxidative stress. Oxidative stress occurs when the body produces free radicals in response to the oxygen-rich environment created by increased respiration that goes with aerobic training. The free radicals need to be neutralized; otherwise, they damage cells and cause premature aging, which leads to chronic inflammation. Chronic inflammation has been termed “the silent killer” and is caused by a lot of “unhealthy” behaviors, such as having a diet high in trans fats or gluten, and being sedentary. People are often surprised to hear that a “healthy” behavior such as aerobic exercise can cause chronic inflammation, but it does.
Research performed on rats has shown that the negative effects of intense aerobic training can be mitigated by taking antioxidants, specifically vitamin E, selenium, and zinc. A study in the journal Free Radical Research
found that vitamin E has a protective effect against oxidative stress in rats that performed intense aerobic swimming. In contrast, the control group rats that did not receive the vitamin E supplement had decreased size of the reproductive organs (testes and accessory sex organs), lower testosterone and related androgen markers, and inflammation and dysfunction of the reproductive organs. Researchers suggest that vitamin E elevates scavenger enzyme activity and gets rid of free radicals, effectively detoxifying the reproductive system of oxidative chemicals.
Take note that the rats performed intense amounts of aerobic swimming—three hours a day, five days a week for four weeks, which is in line with what someone might perform running-wise to prepare for a marathon. And, elite aerobic athletes do this quantity of exercise regularly for many years.
A second study using zinc and selenium for the antioxidants supports these findings. The same intense aerobic exercise protocol was used and the rats who received no supplement had the same harmful effects on their reproductive systems, and they were also found to be significantly less fertile due to the low testosterone and fewer fertile sperm. Their cortisol was also very high. Researchers suggest the antioxidants had a strong stimulatory effect on production of sperm and the androgen hormones, supporting fertility. Zinc and selenium also fought the free radical attack, effectively lowering the inflammatory response.
A 2001 Sports Medicine
review of antioxidant use to counter oxidative stress from aerobic training supports the use of antioxidants, of which vitamin E is most commonly tested and most effective. Antioxidant mixtures of beta carotene and the vitamins C and E also appear to be protective. Results from human studies haven’t been as conclusive as those performed on rats because with animal studies the experiment can be more closely controlled and the animals are forced to complete very intense long duration aerobic exercise, whereas with humans there are more unknown factors. Also, diet, genetic disposition, and exercise history can result in a significant variation in the inflammatory effects of aerobic exercise.
For aerobic athletes, the potential for protection from antioxidant supplementation is “tremendous” and “consumption of a diet rich in different antioxidants is a prudent course of action,” conclude researchers from the 2001 Sports Medicine
review. In addition to the nutrients already mentioned, it is possible magnesium, probiotics, gotu kola, and vitamin D will also help counter oxidative stress from training. Eating fruits high in antioxidants, such as berries, particularly raspberries, strawberries, and tart cherries is recommended because they have been shown to have anti-inflammatory effects in athletes.
Perform Strength Training
Everybody should perform strength training. Naturally, the type and protocol of the training will vary according to goals, age, and health complications, but everyone will benefit from exercises that improve strength, especially endurance athletes and aerobic devotees. Researchers have suggested that because strength training lowers chronic inflammation and provides protection against oxidative stress, it is an ideal solution for coaches and athletes who are concerned about free radical-mediated damage from exercise. This means that simply adding strength training to an aerobic exercise program may counter many of the negatives of aerobics
One recent study in the Journal of Strength and Conditioning Research
compared the inflammatory response of two resistance training protocols after six weeks. Both a hypertrophy and strength protocol were effective at reducing oxidative stress and lowering inflammatory biomarkers over pre-training levels. Researchers found that both protocols resulted in lower inflammation, and they suggest that endurance athletes perform resistance training rather than supplement with antioxidants to decrease oxidative stress.
Aerobic Athletes Will Lose Body Fat & Improve Performance by Strength Training
Another new study in the Scandinavian Journal of Medicine and Science in Sports
shows how adding a strength protocol into aerobic training programs will improve performance and lead to a better body composition for elite aerobic athletes. The study didn’t directly test for oxidative stress or cortisol but it measured body fat, muscle cross sectional area, and short- and long-term endurance capacity in two groups of elite aerobic cyclists: an aerobic-only group that just performed their normal training and an aerobic/strength group that performed normal training with a strength program for 16 weeks.
Researchers found that the aerobic/strength group decreased body fat significantly by an average of two percent from 12 to 10 percent, while body fat remained unchanged in the aerobic-only group.
Other significant improvements in the aerobics/strength group that weren’t seen in the aerobics-only group were increased quadriceps strengths by 12 percent, better performance in a 45-minute time trial, and slightly better performance in a 5-minute time trial. There were no negative effects of strength training for the aerobic/strength group, such as increased body weight or hypertrophy—both common concerns because elite aerobic athletes mistakenly believe that gaining strength will make them slower.
A study published in the Journal of Strength and Conditioning Research
provides potent evidence for never doing aerobic training without also performing strength training. The article is a review of all previously published evidence on the effects of combining aerobic and strength training. The study found that adding strength training to aerobic programs increased performance, strength, and power.
In contrast, the main negative was that aerobic training alone compromised power output. It’s especially critical that athletes in sports such as basketball, football, tennis, ice hockey, and volleyball be able to produce peak power, meaning they should never do aerobic training. Rather, interval sprints are ideal for conditioning and will produce less oxidative stress and a better hormonal response. Sprints have been shown to raise growth hormone, insulin-like growth factor-1, and produce a favorable testosterone to cortisol ratio.
Obviously, if you plan to run 26 miles in a marathon, sprint training alone will not be effective. Instead, add strength training to your regular aerobic training and you’ll have a better hormonal response, and less body fat, according to the Journal of Strength and Conditioning Research
review mentioned above. Aerobic athletes who added strength training to their programs lost body fat, while aerobic training alone did not lead to fat loss.
Practice Judo or Martial Arts
Start practicing judo or a similar martial art to increase antioxidant capacity and decrease oxidative stress. A study in the Journal of Strength and Conditioning Research found that practicing judo can increase resting antioxidant levels that counteract the oxidative stress produced during strenuous exercise. Researchers compared the effects of a mixed exercise protocol that included an all-out sprint Wingate test followed by 30 minutes of aerobic exercise at 60 percent of maximal aerobic power in judokas and sedentary subjects.
Both groups had similarly elevated free radical levels after the exercise test, but the judokas had much greater total antioxidant status at all time points before and after the test than the sedentary group. The judokas’ elevated antioxidant levels indicate a protective effect against the oxidative stress of aerobic exercise. This is the same positive health effect that strength training provides for aerobic trainees, and it’s likely that yoga or other martial arts, such as tae kwon do, will also elevate antioxidants to counteract the many negatives of aerobic training. Such practices may also lower cortisol if they have a calming effect on the body
Take Creatine to Lower Inflammation and Oxidative Stress
Take creatine to lower inflammatory biomarkers and oxidative stress from aerobic training. There are all kinds of benefits from supplementing with creatine because it is the first energy source called on by the body—it’s been shown to increase work capacity and power, elevate protein synthesis after strength training, improve skill execution when tired, and lower oxidative stress from aerobic training.
Recent research shows creatine can inhibit oxidative stress markers following acute aerobic exercise in rats. A study in Amino Acids
found that giving creatine to rats that performed moderate aerobic exercise raised antioxidant levels in the blood, which resulted in lower oxidative stress and less lipid peroxidation than a control group that got no creatine. A second study in the European Journal of Applied Physiology
tested different inflammatory biomarkers and found similarly protective effects from creatine supplementation after aerobic exercise. In both cases, researchers think that creatine increased antioxidant capacity that was able to scavenge the free radicals.
Although these studies showed creatine to be effective to counter the inflammatory response of acute training, it is applicable to the longer term negative effects of aerobic training as well. Evidence into the role of creatine on chronic inflammation without aerobic training supports this. One study in the British Journal of Nutrition
showed that adding creatine to the diet of rats resulted in greater blood antioxidant content and lower inflammatory biomarkers than a control group that did not consume additional creatine.
Supplement With Omega-3s to Reduce Inflammation
Omega-3s are a well accepted supplement to fight inflammation from many sources, and they have been shown to significantly lower oxidative stress markers from aerobic endurance exercise. There are at least 40 studies in the last two years supporting the protective effect of omega-3s on oxidative stress. In fact, the New York City Marathon organizers should give all runners a bottle of omega-3s to combat the damage they are doing to their bodies by running 26 miles.
A 2009 study in Lipids in Health and Disease
measured the effect of omega-3 supplementation on inflammatory biomarkers in men with a history of performing aerobic training. Researchers note that the oxidative stress caused by training can overwhelm the body’s available antioxidant defenses and damage tissues—especially reproductive organs. The subjects in this study were males who exercised at least three days a week for 30 minutes. They were given a total of 4000 mg of omega-3s daily for six weeks, while continuing to perform their regular aerobic exercise.
The group that took the omega-3s had lower resting levels of inflammation after six weeks than a control group that did not supplement. Researchers suggest the protective effects of the omega-3s may have been greater if participants had regularly done more intense aerobic training—in this study their training wasn’t monitored, it just had to be three days a week for thirty minutes.
Top Five Ways To Protect Yourself From the Negatives of Aerobic Training
1) Do strength and anaerobic training instead.
2) Do strength training in addition to your aerobic training.
3) Get lots of antioxidants: vitamin E, selenium, zinc, red raspberries, tart cherries, etc.
4) Take creatine
5) Take omega-3s
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