It’s important to make time for cardio

If you care about your overall health, you need to do some cardio.

Your resting heart rate (RHR), heart rate variability (HRV) and VO2 max (the volume of oxygen your body uses while exercising as hard as you can) are usually much better predictors of your future health and longevity than how much you can squat or bench.

That doesn't mean you don’t need to lift weights and build strength because you absolutely do. Strength training protects your bones and joints from injury and helps to improve balance, reduces body fat, increases stamina and improves overall health. Regular strength training also has a host of mental health benefits like reduced symptoms of anxiety and depression.

But as your aerobic fitness improves so does your ability to mitigate against inflammation, which is why higher aerobic fitness levels are usually associated with longer, healthier lives.

VO2 Max

If you know your RHR, you can ‘guesstimate’ your VO2 max. Simply multiply your age in years by 0.7 and then deduct that figure from 208 to calculate your maximum heart rate, then divide that maximum heart rate figure by your resting heart rate and multiplying by 15.3. The result is your VO2 max in ml/kg/min.

But in reality, it’s very hard to measure VO2 accurately without hooking yourself up to a mask and a heart rate monitor while running or cycling in a lab.

The two best - and easiest - metrics to track (largely because there are so many wearables out there) are Resting Heart Rate (RHR) and Heart Rate Variability (HRV).

Resting Heart Rate (RHR)

A lower heart rate at rest implies more efficient heart function and better cardiovascular fitness and is a good general marker for overall aerobic fitness. It also correlates well with other markers, such as VO2 max.

Elevated RHR in contrast is often associated with higher blood pressure, increased risk of hypertension (and diabetes) and all cause mortality.

Although the official normal RHR ranges from 60 to 100 beats per minute (bpm), the range for most healthy adults is between 55 and 75 bpm, depending on your age.

Heart Rate Variability (HRV)

People with higher HRV tend to have higher aerobic fitness, are generally better at managing stress more effectively, and recover faster from exercise.

A “good” HRV is generally considered to be between 40 to 100 (the number refers to the millisecond variation between heartbeats) but that varies depending on age, fitness level, and overall health. HRV also fluctuates throughout the day and from one day to the next.

The good news is that, in general, the same approaches you would take to lower your resting heart rate can also increase heart rate variability, such as increasing cardiovascular fitness, maintaining a healthy weight, reducing stress and getting sufficient sleep.