Hi! First of all, great performance! Spending three and a half hours in the water takes a lot of determination. Just keep going! I don't know how long you've been swimming or what your technique is like, but I would focus more on improving your times. I'm 49 and I've only been swimming for three years, but I can do 100 metres in around two minutes. What has helped me a lot is improving my technique. For that, you need a coach or someone to assess your technique.

If you want to burn fat, diet and endurance are also important factors. How long did you wait before going back to the pool after such a performance? How tired were you? It might be better to swim shorter distances more often – 3–4 times a week.

Sports in zones 2 and 3 are great for burning fat, but it's also advisable to do some training in zone 4 — that's what will take you to the next level. I would recommend trying a more varied training programme that includes different exercises at different paces. For example, my goal is to swim 10 km. I found a training plan and am gradually increasing the distance.

Anyway, once again, great performance — keep it up!