A 34-year-old who worked out regularly and ate healthily noticed blood in his poop. He had stage 3 colon cancer.

• At 34, Josh Herting led a healthy lifestyle but noticed blood in his stool.
• He was proactive and got a colonoscopy, which came back positive for colon cancer.

In late 2013, Josh Herting, then 34, noticed some clotted blood in his stool.

But because he worked out five to six times a week and ate a healthy diet, he had no reason to think there was anything wrong, he told Business Insider.

"I was just overall really active and in really good shape," Herting, who is based in Massachusetts, said.

Although Herting wasn't in any pain, he knew what he was experiencing wasn't normal. So he Googled his symptoms and shared his concerns with his girlfriend, who put him in touch with a friend who was a gastroenterologist.

The doctor recommended he consider getting a colonoscopy, where a tiny camera on the end of a tube is inserted into the bowels and is recommended for people experiencing rectal bleeding, blood in the stool, constipation, diarrhea that doesn't go away, or unexplained weight loss. He had the procedure on Martin Luther King Day in 2014.

"I'm just so glad I didn't just write it off because I think, unfortunately, a lot of people probably in their busy lives just do see something and think, 'Oh, it's nothing,'" Herting said.

Two days after the colonoscopy, he had just checked into his hotel on a work trip when the doctor called to tell him he had colon cancer.

"It was a huge, huge shock and pretty much flipped my life upside down," he said. "I had no idea that there was something like cancer that could be wrong with me."

He was told to come home right away for urgent medical appointments at 8 a.m. the next morning.

Colorectal cancer cases are rising in younger people

Herting became one of the rising number of young Americans diagnosed with early-onset colon cancer.

Colorectal cancer, which is an umbrella term for cancers that affect the colon or rectum, is the leading cause of cancer death in men under 50 and the second deadliest cancer for women of the same age, according to the American Cancer Society's latest report.

Colorectal cancer cases have been rising each year since the late '90s, while deaths of people under 55 have increased by about 1% a year since the mid-2000s, the ACS report found.

BI previously reported that experts believe lifestyle factors such as being obese, leading a sedentary life, and drinking too much alcohol are playing a role.

"What we suspect may be happening is that whatever combination of environmental factors is responsible for this, that it's likely changing our microbiomes or our immune systems, leading us to become more susceptible to these cancers at a younger age," Dr. Kimmie Ng, the director of the Young Onset Colorectal Cancer Center at Dana-Farber Cancer Institute in Boston, recently told NBC.

But, one in three people under 50 diagnosed with colorectal cancer have either a genetic predisposition or a family history of the disease, the ACS said.

Herting's dad was diagnosed with stage one colon cancer in his early 50s, but genetic testing showed that this was unrelated to his own diagnosis.

Herting had surgery and six months of chemotherapy

Around two weeks after his diagnosis, Herting had surgery to remove the cancer from his colon, and doctors discovered that it had spread to some of his lymph nodes, making it stage 3a.

He was told having chemotherapy would give him the best chance of survival, so he had 12 rounds over six months. The side effects of chemotherapy were difficult, including chipped teeth, cavities, loss of sensitivity in his hands and feet, and memory problems.

Herting has gained the feeling back in his hands and feet but says his memory has never been the same. "I'm not the same person I was for multiple reasons, but this is what it looks like to survive cancer," he said.

His treatment was successful. For the next six years, he had a yearly CAT scan to check if the cancer had returned but, at 44, Herting is cancer-free.

Symptoms of colorectal cancer include bloody poop, weight loss, and fatigue

Things are going great for Herting, he said, and in the 10 years since his diagnosis, he married his girlfriend and had two kids. "I feel really lucky, and it emotionally taught me a lot about being thankful for every day," he said.

He's sharing his story to help raise awareness of the signs and symptoms of colon cancer and to encourage people to be proactive if they notice anything.

"As much as you think a colonoscopy isn't fun, colon cancer is a million times worse," he said.

Symptoms typically include abdominal pain, weight loss, weakness and fatigue, blood in the stool, the feeling that you need to poop that doesn't go away once you've been to the toilet, and changes in bowel habits such as diarrhea and constipation.

However, research suggests that there are four specific symptoms of colon cancer common in younger people: abdominal pain, rectal bleeding, diarrhea, and iron deficiency, in the three-month to two-year period before getting diagnosed.

"If we can make people more aware of what signs to look for and to monitor themselves and what's going on in their body, I think that would be a positive because colon cancer is very preventable," Herting said.