Many kettlebell users experience an increase in endurance when doing activities like sports. There have even been reports of kettlebell users who have run marathons without training for marathons but by only using kettlebells! https://bit.ly/2G2DNk7
Feeling good is very important to having a productive life. Kettlebell users from all over the world report having increased energy and even feel like they can reverse the hands of time, often fixing injuries that have nagged them for years. This allows them to participate in activities they had stopped doing because of the injuries.