FITNESS
TRAIN THE
MUSCLE THAT MATTERS MOST
BY JOLENE MORTIMER, BIOKINETICIST, SPORT SCIENTIST, AND DIRECTOR, METAWELL
Every spring, on cue, the six-week challenges appear. This year, amid the rush to train the mirror muscles, it may be time to give the heart some attention.
Summer is coming and suddenly we are training glutes, chasing abs, and adding an extra chest day. Ask someone how much they bench and there is a reasonable chance they’ ll know the answer; ask about their cardiovascular fitness and things become a little less certain.
We even have a name for the favourites. The“ mirror muscles”: chest, biceps, shoulders, quadriceps, and everything else we can see when we look in the mirror.
Meanwhile, another muscle works 24 hours a day, seven days a week, without a progress selfie or much applause at all. It beats around 100 000 times a day and, unlike your biceps, taking a rest day is not really a choice.
This spring, it is worth giving the heart some training too. What we casually call“ cardio” is really a conversation between several systems. Your heart pumps oxygenated blood towards working muscles while your lungs bring oxygen in and remove carbon dioxide.
Blood vessels regulate flow, muscles extract and use the oxygen delivered to them, and mitochondria help convert available fuel into the energy required to keep you moving. Repeat that demand regularly and the entire system becomes more efficient. The heart can pump more blood with each beat, working
74 INBOUND SA / SEPTEMBER 2026