People.com Royals How Prince William, Princess Kate and Prince Harry's Mental Health Initiative Is Resonating with the Public Two veterans, who are running the London marathon six days after completing the Boston run for the royals' Heads Together campaign, praise the trio for their "guts" By Simon Perry Published on April 22, 2017 08:56 AM Share Tweet Pin Email Photo: Karwai Tang/WireImage In the six days between their back-to-back marathons (the Boston marathon last Monday and the London race this Sunday), veterans Ivan Castro and Karl Hinett have noticed an ocean-spanning growth in awareness about mental health problems, thanks in part to the British royals’ Heads Together initiative. The campaign will reach a high point on Sunday when Castro, from North Carolina, and Hinett, from Birmingham, England, join a large group of runners at Sunday’s London Marathon who are racing on behalf of Heads Together. Castro, who lost his sight when he was injured in combat in Yusufiyah, Iraq, in 2006, was with Prince Harry during his 2013 expedition to the South Pole and he has taken part in two Invictus Games. “In all my times around Prince Harry I never ever bring up the passing of his mother and to see him openly say that now, it takes a lot of guts to do that,” Castro tells PEOPLE. “Having high profile figures – you saw Prince William spoke with Lady Gaga – come out and talk about it, really starts the conversation and breaks that taboo.” Kirsty Wigglesworth/WPA Pool/Getty Images Hinett, who was left with 37 percent of his body badly burned after an injury while serving in Basra, Iraq, in 2005 agrees that the royals have had an impact. “They are very high-profile figures and the issues that they are talking about are very relatable,” he tells PEOPLE. “They are coming across as very real to the public. You can feel how sincere they are and how important a cause it is to them. It’s resonating to everyone else. Them reaching out is helping a lot of people step forward and admit that they need some help and make people realize that there is help out there for whatever they may be dealing with.” RELATED VIDEO: Our Favorite Trio Prince William, Princess Kate and Prince Harry Launch Their ‘Heads Together’ Campaign As they gear up for Sunday’s race, the men add that a high-point of their marathon week was being able to cross the finish line at the Boston marathon together — and holding each other’s national flag. Kirsty Wigglesworth/WPA Pool/Getty Images “I have plenty of friends who suffer mental health injuries and to be apart of it and give back to my friends,” says Castro. “To run across the finish line with the U.K. flag was great.” Both say that physical activity and exercise has helped them with their recovery. “I used running as a form of potential therapy to dig me out of any potential holes I found myself on,” Hinett says. Castro says he is “excited” about London. “I’m so pumped out and I hope it wont be the last time I run with Karl. I consider him a brother in arms.” Hinett adds, “I’m looking forward to seeing a sea of blue with everyone with their [Heads Together] headbands on. To transform such a high profile race and call it the mental health marathon is very exciting and sharing it with Ivan makes it even better.” And they both have a little friendly rivalry going on – each are trying to out-do the other in a fundraiser for a 1,000-mile bike ride. If Castro wins, he and Hinett will do the bike ride in America. If Hinett wins, they will both ride in the U.K. So far, both have raised $173,000 for Heads Together. Click here to back Castro and click here to support Hinett.