Very unhealthy, generally. Sumo wrestlers live about 20 years less than their peers.
All that physical exercise puts a strain on the body and the extra weight makes it way worse. Exercise is healthy up to a point (and that point is way, way beyond what anyone casually hits), but more isn’t always better.
Many athletes require strength and speed and they train themselves to build muscles which tend to make them heavier than an average person. Good athletes also manage their diets fairly strictly. So in that sense, you can consider them healthy.
However, at the more extreme ends, high performing athletes/professionals, this can be rather unhealthy in the long term. While they also have to manage diet and exercise, they tend to accumulate injuries and chronic problems. This is why many athletes cannot perform at the top levels for very long (maybe 10-15 years). After that, they tend to scale back but their good dieting and exercise habits usually allow them to maintain a healthy “normal” weight. However injuries don’t always go away completely over time so there may be a toll on their health.
Some kind of athletes, like sumo – lead really unhealthy lives. They tend to die young. One aspect of modern athletics is the use of drugs. While this can enhance performance, this quite often lead to long term health problems.
Regular exercise does give some allowance for additional weight especially for athletes but this is likely only true until they scale back.
I think you need to separate healthy and athletic.
It’s healthier to be a 300 pound strongman or lineman or sumo wrestler; than it is be a 300 pound “blob” of a person…..but it’s not healthier than the average person.
At the same time many of these “big boy” athletes are far more athletic than the average person.
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