A 28-year-old man is determined to walk 250,000 steps in one week to see what happens: The shocking results revealed

Recording his experience in a video that attracted over 1.5 million views, the man revealed the terrifying impact of this challenge.

British YouTuber Jack Massey Welsh noticed significant changes in his body after just one week of walking the streets, covering an incredible distance.

Welsh walked a total of 250,000 steps in just seven days, averaging 35,700 steps per day, which is equivalent to 17 miles (about 27.3 km), more than half the distance of a marathon.

This number is about ten times higher than the 3,000 to 4,000 steps that the average Briton is estimated to take each day and 3.5 times higher than the 10,000 steps per day that some experts recommend.

Recording this experience in a video that has gained over 1.5 million views, Welsh revealed the harsh effects of the challenge.

He endured severe pain in his legs, swollen ankles, and "black" toenails that appeared a few days after completing the 250,000 steps.

But what surprised Welsh the most were the physical changes he noticed—changes he never thought could be achieved simply by walking.

"It was such a great sense of achievement. A quarter of a million steps in one week. For me, this experience alone was worth it," he said.

Before starting the challenge, Welsh didn’t change his diet except for eating more protein to reduce fat instead of muscle when walking.

He also weighed himself and measured parts of his body, like his waist and legs, to compare any differences at the end.

On the first day, Welsh started the challenge by walking 15,500 steps in two hours in the morning, then 14,000 steps before hitting his daily target by taking a short walk with his dog in the evening.

On day one, he said: "I'm tired, but I'm okay. Just one more step."

These words haunted Welsh on the second day, as he was still in pain from the previous day's effort.

"I reflected on how overly confident I was on the first day. When I confidently said, just one more step, because now taking one more step is no easy task," he said.

"Really, every step was painful and exhausting."

However, Welsh found that he quickly adapted to the challenge and adjusted his routine to try and meet most of his step goals during the lengthy morning walks.

By day four, he said the muscle pain in his legs had subsided but mentioned that he started to experience other physical issues.

"The only limiting factor I feel in this challenge is joint pain in my legs. Because even though I have enough energy to easily walk 30,000 steps today, every step is quite painful, and I'm starting to get blisters in a few places, so that's what slowed me down."

By day five, he had to use painkillers to walk due to foot pain, with viewers noticing his feet covered in blisters, and by day six, he also had swollen ankles.

But when sharing at the end of the challenge, he said he had a "great sense of achievement" after counting down the last steps to reach 250,000.

He also detailed the changes in his body after just one week of intense walking, including overall physical changes.

Comparing before and after photos, he said: "I look slimmer than when I started, which I didn’t expect. Does this mean I've lost some muscle mass?"

He also noted that he had lost some belly fat on his sides, attributing this to a 0.9 kg weight loss during the week.

Measuring with a tape measure showed that most areas, such as the circumference of his arms and torso, had shrunk slightly, except for his thighs, which had increased by 0.5 cm.

Though not during the challenge itself, Welsh also shared with viewers that the toenail of his right foot turned black two days after reaching the 250,000-step target.

In conclusion, he said: "Would I recommend walking 250,000 steps a week? Definitely not. My joints can’t keep up, and it’s been two days, and I'm still waiting for the swelling around my ankle to go down."

However, he advised people to consider counting steps more reasonably throughout the day.

"Would I recommend walking between 8,000 to 20,000 steps a day, depending on your personal fitness? Absolutely," he said.

"I truly feel that most people would feel better if they walked more."

Experts suggest that people should not focus too much on hitting the 10,000-step target, as benefits can be seen with just 4,000 steps a day. Instead of focusing on the number, brisk walking for 10 minutes a day can offer many health benefits, and this activity contributes to the recommended 150 minutes of exercise per week for adults.