Negative Effects of Too Much Daily Intense Exercise

Psychgrrl

Thought this summary was really interesting. Especially the drastic change between 90 minutes (great!) and 152 minutes (not so good). I do a lot of interval training, and rarely go as long as 90 minutes. And because it’s interval training, it’s not all intense.

https://apple.news/AcL65unUjR9ilQW1mdAALZA

PS I found the title a little melodramatic, so I renamed it. 😊

Thoin

I really love interval training. I just hope it really does work like they think it does.

TakeTheLongWayHome

I just got over something like this. I had been going every single day cranked to 11. Thing is, I knew I was probably overdoing it, but I felt great. Until I didn’t. Just had no energy for a day and a half. Hopped on my bike yesterday and shook it off.

Psychgrrl

TakeTheLongWayHome wrote: »

I just got over something like this. I had been going every single day cranked to 11. Thing is, I knew I was probably overdoing it, but I felt great. Until I didn’t. Just had no energy for a day and a half. Hopped on my bike yesterday and shook it off.

Hope you’re feeling better for good! I love pushing it hard during the intervals, but they wipe me out.

Theo166

The apple link didn't work for me
searched for a direct link: https://www.theladders.com/career-advice/if-you-exercise-more-than-this-amount-of-time-per-day-the-results-are-disastrous


This makes me wonder how it relates to serious athletes. When young and in my prime, I recall exercising up to 4 hrs a day and swimming 7 miles a day in total distance.

Psychgrrl

I wondered that, too. I think the issue is the intensity, and maintaining it for 152 minutes directly. I don’t have a deep understanding of training for elite athletes, but I did work with student athletes at a D1 school. I rarely saw them perform nonstop at a high intensity for more than few minutes at a time. There were always bouts of lower intensity in between the super high intensity.

bubus05

Arnold Schwarzenegger said, when asked how much time one needs to spend in a gym, 'if you are there more than an hour you are doing it wrong'.
I am not sure in what context he said it though, he probably meant at any one time because as a pro he was training three times a day. I think there is such a thing as overtraining especially while doing a HIIT training. A relatively slow cardio like a road bike ride can easily last more than that but high intensity interval probably should be kept under an hour.

charmmeth

This seems to be researching the effects of continuous high intensity exercise, and I think it is pretty clear that this is not great for the body. Also, I was left wth some questions about how active their test group was outwith this particular form of exercise?

I quite often do an hour or more of exercise in the morning, especially if I have a long day of meetings (=sitting at my desk) coming up. I mix forms of HIIT with rowing (often ome form of pyramid, so varied intensity) and stretching. This quite often puts me over the 152 minutes of exercise in total for a week, but I suspect it does not put me over 90 minutes of high intensty, given the varying intensity of what I do. This is anecdotal, but over a period of months, I certainly don't feel that I have had any of the negative effects described here. So my question would be: what form of exercise was the sample group doing?

AnnPT77

charmmeth wrote: »

This seems to be researching the effects of continuous high intensity exercise, and I think it is pretty clear that this is not great for the body. Also, I was left wth some questions about how active their test group was outwith this particular form of exercise?

I quite often do an hour or more of exercise in the morning, especially if I have a long day of meetings (=sitting at my desk) coming up. I mix forms of HIIT with rowing (often ome form of pyramid, so varied intensity) and stretching. This quite often puts me over the 152 minutes of exercise in total for a week, but I suspect it does not put me over 90 minutes of high intensty, given the varying intensity of what I do. This is anecdotal, but over a period of months, I certainly don't feel that I have had any of the negative effects described here. So my question would be: what form of exercise was the sample group doing?

Did you read the linked article at TheScientist? There's much more detail in that about the type of exercise (stationary bike) and how it was structured (type of intervals and whatnot).

https://www.the-scientist.com/news-opinion/extreme-exercise-carries-metabolic-consequences-study-68581

There's also a little more info there about the elite athletes part of the research, and its implications.

The actual research writeup in Cell Metabolism seems to be paywalled, but the summary (with select graphics) is available here, along with the details needed to access the article if you have a institutional access some way, or are willing to pay:

https://www.sciencedirect.com/science/article/abs/pii/S1550413121001029?via=ihub

FWIW, this is just personal opinion, but the other content I linked above makes the study sound less dippy. Reading the first-linked post, I was thinking "no one outside the calorie-obsessed blogosphere is structuring their whole exercise life as entirely *true* high intensity, all the time, are they?". I admit, extreme high intensity is exhilarating (I've done max-effort intervals in the larger context of a training program, and max effort in races, up to measured HRmax) . . . but it's clearly fatiguing way, way disproportionate to fitness or calorie benefits.

Coaches I know don't structure high-level successful programs that way, it's inconsistent with what I learned in coaching education, etc. Even here on MFP (and in my real life, based on friends/acquaintances), the serious recreational athletes are using some kind of structured, varied-intensity program to improve fitness and performance (sometimes a pretty detailed, complicated periodized program), not just going max hard every time.

So, the initial article made the study seem more like a debunking of things that well-informed coaches/athletes wouldn't do in the first place, which was kind of surprising to me, coming from serious academics. With the additional details, though, it looks like the study's focus was at least partly on *why* "all high intensity all the time" may not be a great idea, alongside looking for where the approximate "overdoing" line might be in relatively untrained people.

It seems like another situation where there's a gee-whiz blogosphere pop-practice view (that pulls little bits of science out of context and runs with them beyond all rationality); and a more serious, disciplined realm where a more well-rounded view of the science is put in practice . . . kind of like the gee-whiz side of diet/nutrition ("No white foods!" "protein shakes and green smoothies for all!" "IF and low carb is universally essential for weight loss because evil insulinz!"), vs. the better-rounded science, which is more complicated, and leads to more nuanced, complicated practice.

Call me cynical, I guess.

Spotteddingo

From my own personal experience I do believe that intense, prolonged exercise causes inflammation and is not good for your body.

I was an open water endurance swimmer for 12 years(until Aug. 2019) and I also cycled and ran for a bit. I trained almost everyday and sometimes several times a day, training others. It can be addictive just like anything else. I started having heart arrhythmia, achilles and hip issues. Two orthopedics told me that I needed to stop but I just wanted to go farther, faster!

It hit me that I was not doing myself any favors when I started looking for 10 mile open water races. That and wearing out a hip got me to finally stop. A cardiologist also told me that ultra marathoners and endurance athletes often have heart issues as early as their 50's.

I loved my workouts but know now that I can get great benefits from much more moderate exercise.

heybales

Bugs me when studies like that call 4 or 8 min intervals HIIT.
Compared to intensity level in 30-90 sec intervals.

That's just good old SIT (Short IT) - which still points out the potential negatives when overdone.

So whether an athlete that could do longer sets of intervals, or more intense - there's usually a reason why their coaches don't have them.

That protocol though, and on a road bike, totally fits in with another study from years ago about recreational cyclist that do lots of group rides, little specific training.
While they do improve in fitness and ability, it's usually much slower than coach led ones trying to enter the pro-field with young ones that still have a job-life.
It came down to basically the same thing - every group ride was pretty intense, very interval in nature at high level for pretty long periods of time. Very slow improvement compared to focused training, that many times wasn't even the same volume of intensity.
So this study is very interesting as to why it's likely happening.

charmmeth

AnnPT77 wrote: »

Did you read the linked article at TheScientist? There's much more detail in that about the type of exercise (stationary bike) and how it was structured (type of intervals and whatnot).

There's also a little more info there about the elite athletes part of the research, and its implications.

The actual research writeup in Cell Metabolism seems to be paywalled, but the summary (with select graphics) is available here, along with the details needed to access the article if you have a institutional access some way, or are willing to pay:

FWIW, this is just personal opinion, but the other content I linked above makes the study sound less dippy. Reading the first-linked post, I was thinking "no one outside the calorie-obsessed blogosphere is structuring their whole exercise life as entirely *true* high intensity, all the time, are they?". I admit, extreme high intensity is exhilarating (I've done max-effort intervals in the larger context of a training program, and max effort in races, up to measured HRmax) . . . but it's clearly fatiguing way, way disproportionate to fitness or calorie benefits.

Coaches I know don't structure high-level successful programs that way, it's inconsistent with what I learned in coaching education, etc. Even here on MFP (and in my real life, based on friends/acquaintances), the serious recreational athletes are using some kind of structured, varied-intensity program to improve fitness and performance (sometimes a pretty detailed, complicated periodized program), not just going max hard every time.

So, the initial article made the study seem more like a debunking of things that well-informed coaches/athletes wouldn't do in the first place, which was kind of surprising to me, coming from serious academics. With the additional details, though, it looks like the study's focus was at least partly on *why* "all high intensity all the time" may not be a great idea, alongside looking for where the approximate "overdoing" line might be in relatively untrained people.

It seems like another situation where there's a gee-whiz blogosphere pop-practice view (that pulls little bits of science out of context and runs with them beyond all rationality); and a more serious, disciplined realm where a more well-rounded view of the science is put in practice . . . kind of like the gee-whiz side of diet/nutrition ("No white foods!" "protein shakes and green smoothies for all!" "IF and low carb is universally essential for weight loss because evil insulinz!"), vs. the better-rounded science, which is more complicated, and leads to more nuanced, complicated practice.

Thank you for posting the links, Ann. I've looked a them (and my uni has access to the actual research) and I agree: what they are trying to establish was what "over training" might look like. What I find odd given the aim of the research is that massive jump from 90 minutes/week (which came in with real benefits) and 152 hours per week (which came in as over training). The detailed article didn't answer my question as to what their subjects' activity looked like outwith the HIIT periods, which I think is not irrelevant. The discussion of actual elite athletes is fascinating and as you say complex. My conclusion from this is that it's unlikely that my levels of exercise are actually causing me any harm, even though I regularly do between 400 and 550 minutes/week. What I do is not going to be anything like as high intensity as described here.

FitAgainBy55

"For the sake of this analysis, the researchers defined over-exertion as high-intensity exercises that exceed 152 minutes, cumulatively."

When I participated in endurance races, the plan that I followed included only 1 day per week of high intensity interval training. My speed work days never exceeded 45 minutes. From talking to others, this is a fairly typical structure.

I don't think this study is relevant for the vast majority of people.

A more interesting study and one that became a very popular point of discussion in the running community concluded that running more than 20 miles per week or faster than 8 mph exceeded the point of diminishing return for risk of death.

Like @Spotteddingo I've stopped endurance racing. I was never diagnosed with a heart arrhythmia but I did eventually get to the point where I felt my heart 'flutter' on occasion at rest -- which I always assumed was an arrhythmia. I also eventually developed achilles tendonitis. I plan to stick to a max of around 20 miles per week at an easy pace and focus more on strength training for a well rounded fitness plan.

https://www.active.com/health/articles/why-too-much-running-is-bad-for-your-health
"Overall, runners had a 19 percent lower death risk than non-runners. However, the health benefits of exercise seemed to diminish among people who ran more than 20 miles a week, more than six days a week, or faster than eight miles an hour. The sweet spot appears to be five to 19 miles per week at a pace of six to seven miles per hour, spread throughout three or four sessions per week. Runners who followed these guidelines reaped the greatest health benefits: their risk of death dropped by 25 percent"

Spotteddingo

@FitAgainBy55
Arrhythmia does feel like a flutter and is worrisome although not considered a real problem. I like what you posted about running and the sweet spot.