FITNESS muscles become much better at extracting and using oxygen, and adaptations within the capillary network and mitochondria support the production of aerobic energy.
Over time, the same physical task simply costs your body less. You notice that improvement in everyday life when you get through an airport with your luggage without feeling flattened, recover more quickly from a flight of stairs, explore somewhere new on foot, or swim in the sea and still have enough left in the tank for the rest of the day.
Fitness is not about how much punishment you can tolerate; it is about how efficiently your body can meet a demand and recover from it.
Running is an excellent way to train this system, but it certainly is not the only one. Walking, hiking, swimming, cycling, stairs, dancing, and continuous low-impact circuits can all provide an effective cardiovascular stimulus. The work does not necessarily need to happen in one continuous bout.
Much of cardiovascular fitness is built through manageable, consistent work, with controlled periods of higher effort added as capacity develops. LIIT fits particularly well into travel because purposeful movement alternates with easier periods, allowing heart rate and breathing to rise while keeping impact and overall fatigue manageable.
One final bit of physiology for when spring enthusiasm kicks in: cardiovascular fitness can begin improving quickly when activity increases, while bones, joints, and tendons need longer to accommodate increased mechanical load. Your lungs feeling fantastic does not automatically mean your Achilles agrees.
Use the warmer weather and longer days to create movement across the day. Walk a little further, swim, take the stairs, add an interval, dance after dinner, or pick up the pace when it feels right.
A 20-minute walk on the beach in the morning, a 20-minute LIIT session around lunchtime, and 20 minutes of dancing after dinner already add up to 60 minutes of accumulated movement across the day. On another day, it might simply be three 10-minute bouts between flights, meals, sightseeing, and family time. Building movement into the rhythm of your day can be far more realistic than treating exercise as another appointment, while still giving the cardiovascular system repeated opportunities to work.
Intensity is personal too. A brisk uphill walk may be comfortable aerobic work for one person and a significant challenge for another. Your breathing is a useful guide. If you can hold a comfortable conversation, you are probably doing easier aerobic work. Shorter sentences suggest that the demand has increased, while managing only a few words at a time means you are working hard. Not every session needs to reach that final level.
Give your body enough stimulus to adapt, enough recovery to do so, and keep coming back to it. Keep training your glutes, strengthening your core, and looking after your back. Just remember the muscle supplying all of them while you are at it. You know, your heart is a muscle too. Quite an important one, as it turns out. IB
SEPTEMBER 2026 / INBOUND SA 75