

The ease with which you can do certain exercises defines whether you are ageing gracefully or aggressively.
Want to test your physical age?
The physical age or biological age reflects cellular damage, metabolic function, and organ efficiency. This is different from your chronological age (as per birthday). Your physical age may be different from your chronological age as you know it. A full-body HIIT workout is one of the best ways to check your physical age and keep it going at a good pace.
We love to go over topics like these because they are a light-hearted reminder to stay fit, regardless of a busy lifestyle. This blog is for people who like to keep tabs on their fitness and longevity.
"Just wait till you are my age." Anytime you hear this, it's a reminder to stay consistent with your fitness routine. Take it as a sign to never give up on your fitness progression. Here is what your physical age depends on:
Now and then, you may notice that some people look younger than their actual age. “You really do not look 50” is seen as a positive compliment for someone who looks healthy and active for their age. The thing is, two people can be 50, yet one may have a different kind of glow. Some people look healthier and give off the energy of someone much younger than their age. Biological age and diet play a big factor here. Many people confuse biological age with physical age.
Let’s take a look at this difference between chronological age vs physical age.
|
Basis |
Chronological Age |
Biological Age |
|
Meaning |
Chronological age is based strictly on your calendar birthday. It never changes or slows down. |
Biological age is based on your physical health, cellular damage, and how well your organs work. |
|
Difference |
Chronological age increases as per your birth year. |
Your biological age can be higher or lower than your actual calendar age depending on habits. |
|
Impact of habits |
Your habits do not change your chronological age. |
Smoking, high stress, poor diet, lack of fruits and essential vitamins may increase biological age. On the other hand, consuming a healthy diet, sleeping well, and exercising are known to lower your biological age. |

The single-leg balance test shows healthy neuromuscular function in adults.
You might be able to do this very easily during childhood. While it seems easy, most people trip over after a few seconds. Having an active lifestyle over the years is the biggest reason for loss of stability. Find out what your biological age is with the following table.
|
Single-Leg Hold Duration |
What it Says About Your Physical Age |
|
30 sec or longer |
30-29 years old |
|
20 to 29 sec |
35 to 49 years old |
|
10 to 19 sec |
55 to 65 years old |
|
5 to 10 sec |
65+ years old |

The physical age is one of the top predictors of longevity and health. If you can successfully pass the single-leg balance test, then boosting your VO2 max is the next step for you. Simple 30-minute HIIT workouts are among the best ways to maintain a healthy physical age.
|
Basis |
SpO₂ |
VO₂ |
|
What is it? |
Blood oxygen saturation |
Maximum oxygen uptake during the HIIT workouts |
|
Definition |
The percentage of oxygenated haemoglobin in your blood relative to total haemoglobin. |
The maximum volume of oxygen your body can use per minute during intense exertion. |
|
Ideal Readings |
An ideal SpO₂ level is between 95% and 100% for most healthy individuals. |
When it comes to VO₂ max, there is no ideal score, as it depends on age, sex and fitness level. |
|
Measuring |
oximeters |
smartwatches or specialised lab masks during a graded exercise |
The single-leg balance test is a common parameter to check the physical age of a person. However, physical performance markers include many more tests, such as the following, as well as other stability tests.

High-intensity interval training (HIIT) lowers your physical age by improving you from within. It improves your cellular health, specifically by:
HIIT stimulates the production of human growth hormone (HGH) in the body. This is the main reason why a full-body HIIT workout helps. This hormone plays an important role in cell repair, muscle growth, and overall longevity.
Faster heart rate recovery signals a younger cardiovascular system.
Take it as a sign during your HIIT workout. This session challenges your VO₂ max, functional strength, mobility, and recovery, which are the key markers of physical age. Track peak heart rate and how fast it drops in recovery. Keep in mind the following things while evaluating your workout.
Equipment Needed
30-Minute Structure
Goal: Raise heart rate and loosen hips, shoulders, and spine.
Format: 4 rounds of a 5-minute circuit
Work: 40 seconds per exercise
Rest: 20 seconds between exercises
Rest between rounds: 1 minute
Complete all 5 exercises back-to-back. Then rest for 1 minute after exercise 5, then start the next round (4 rounds total).
Hold each for 30–45 seconds and breathe deeply. The goal is to bring heart rate down, reset posture, and check how your body feels after high effort.
Use these markers alongside standard tests (grip strength, sitting-rising test, and push-up capacity) to estimate whether your physical age is younger, on par, or older than your chronological age. Repeat this workout every 4–6 weeks to track improvements in VO₂ max, SpO₂, grip strength, and heart rate recovery, which are key signs of slowing or reversing biological ageing.
Looking for HIIT workout routines online for free?
These expert-led sessions on FITPASS TV let you train anytime, anywhere.
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Did you know the different styles of HIIT workouts? Get access to full-body HIIT workouts from the leading fitness coaches across the globe. Try HIIT Tabata, HIIT Cardio, HIIT Mountain Burn, LA30 HIIT, Boxing HIIT, Intense Full-Body Strength HIIT and more on FITPASS TV. |

Many fitness folks across the globe agree that regular exercise, jogging warm-ups and HIIT workout routines are a powerful tool for reversing cellular ageing and boosting longevity.
Your chronological age (birthday) has got nothing to do with your physical age, which is your body’s actual biological age. Looking through a broader lens, you could be 30 with the metabolism of a 50-year-old if you lead an unhealthy lifestyle. On the other hand, if you stay active.
Download the FITPASS app to access the best workout videos on FITPASS TV and learn from the best.