BMI and my challenge

I thought I would do a blog on one of my pet hates about the fitness and health industry and that is the BMI or Body Mass Index. Stick with me through this as there is a reason why I am writing about it.

What is BMI

According to Google it is a numerical value of your weight in relation to your height. There is a formula that you can use to work out the actual BMI result. It is one of those scary looking ones and well advanced for the basic 2+2=4. It is:

Weight (kg)
Height in (m)2

See I told you it looked scary. BMI even comes with a colourful graph to show you which box you may fit in too. They are:

<18.5 is underweight
18.5 to 24.9 is normal weight
25 to 29.9 is overweight
30 to 39.9 is obese
>40 is morbidly obese

And there you have it, the numbers and the definitions.

Why does it annoy me?

It has always annoyed me and has recently cropped up again due to an upcoming appointment. Said appointment will have a BMI reading to determine if we are fit enough to get on to the next stage. Mine is high and I currently sit in the obese category. However, this is where it gets interesting. My legs and arms are quite muscular, but my stomach is where I carry most of my fat. I would be the average apple shape if I had to pick. The whole BMI topic is a hotly debated one and it annoys me greatly as I don’t think it takes people who work in sport or fitness into consideration when it is calculating it. I am sure there are also other industries which can get into hot water with it too but considering I work in fitness I will pick that one.

Let me explain

Take a rugby or a football or a rowing team for example. These guys and girls will train 7 days a week for several hours each day. They will work on their cardio, they will lift weights down the gym, they will make sure their core is up to scratch and they will work hard to achieve their body which will make them win the match or the race.

What happens when we take the BMI from one of them?

For example, lets take imaginary man Stuart who is 6 foot and weighing in at 16 stone. He is built of solid muscle and there is very little fat around him. Stuart’s BMI would be 30 which makes him obese. Just so it is fair let’s also take imaginary Shona who is 5 foot 3 and weighs in at 12 stone 5. The BMI results would be 30 which again pops her into the obese category. Do you see where I am coming from? Stuart and Shona are the fittest they can be, but because muscle weighs more than fat they are in the obese category, even though they are not obese. I am really hoping this makes sense.

NHS BMI Result

What annoyed me even more was when I went on to check my BMI on the NHS website. I understood the first part of putting in my height and weight, but it was the second part on exercise levels that really got me. NHS defines exercise as:

Inactive – less than 30 minutes exercise a week
Moderately active – between 30 and 60 minutes of exercise a week
Active – between 60 and 150 minutes of exercise a week

Now the numbers I understand and please bear in mind that this is bare minimum of exercise a week. This comes down to thirty minutes of exercise over five days of the week. In my opinion you should be aiming for a lot more that 150 minutes a week. Now being a personal trainer and doing my own work outs I am nowhere near any of those numbers. My exercise in minutes for the week does not have a box. And therefore, I average anywhere between 500 to 800 minutes of exercise a week depending on what I am doing. I am several times over the “average”. If people are going to take this number to give me a correct answer to BMI, then I can’t do it as it doesn’t exist. I can get the answer for the height and weight formula, but it stops there.

The challenge

To prove a point, I have decided for the month of July to set myself a little challenge. You are of course welcome to join me in this challenge. All you will need is somewhere to exercise whether it is at a gym, a class, outside in the garden, walking the dog and the list goes on. You will also need somewhere to track down your exercise in minutes. The challenge is to exercise for 1000 minutes a week. This roughly translates as 2 and half hours of exercise every day. It may seem like a lot but if you break it down even further and say walk both to and from work, as well as go for a stroll at lunchtime you can easily do an hour just by that. It also really boosts your mental and physical wellbeing. Add in an hour’s gym class, you have 2 hours and then spend the last 30 minutes in the garden mowing the lawn then all together that is 2 and a half hours done. Say at the weekend you go for a 5 hour walk in one of Scotland’s National Parks then you have a bank of additional hours. And so, on and so forth. It is a challenge after all.


I will keep you updated as we go through July but at present after three days, I am currently on 478 minutes. Not a bad start but still a long way to go.


This Post Has One Comment

  1. Sue Lubkowska

    Interesting article and one I agree with completely.

    I have to say that I am shocked that to qualify as “active” you only have to notch up an hour to two and a half hours exercise a week. That easily puts me in the active category whereas I would describe myself as moderately active. Not sure whether this says more about the general fitness of the nation or the dodgy calculation.

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