Love the mad science!
I’ve sunk to the bottom of the pool many times, which requires breathing out.
Finding neutral buoyancy is okay, but like you say, measuring the air is tricky to say the least.
Might be ‘easier’ with a weight belt and maybe a BCD (inflatable diving vest)? That way rather than expel air you can add weight until you start to sink…?
Or Google where the nearest Dexa scan place is? Can’t even take small hand paddles into my local pool. Balloons and jugs might get you sectioned and a mention in the local paper.
Saw some jugs at a pool in France once
Seems to be one nearby but results are all about bone density, none of them talk about bodyfat
I don’t really understand private medical insurance (despite having worked for them). Do I just phone them up and say I want one, or do I need to convince the GP to ask for one?
I doubt youll get a DEXA scan on PMI just for shits and giggles. There would need to be a medical reason for requiring one.
Only way you might it is if they offer a health screen either free or heavily discounted. They sometimes do a DEXA as part of those.
I think the most usual clinical use of DXA is bone densiometry. Granny might get one of these after she falls and breaks her wrist, or before she falls and breaks her wrist if she is especially well looked after.
My understanding is that the same technology can be used to measure the density of other tissues such as fat, muscle and what have you. But have never actually known anyone get a test for that reason. Imagine you might have to get into the murky world of sports medicine and exericse physiology labs and part with a few coin of the realm, unless perhaps could find a way into some research project as a subject?
There was a guy I knew who was morbidly obese and had a gastric band fitted in the end. He had a few DEXA scans for bodyfat measurements. Not sure if thayvwas part of his surgery plan or he paid for them separately
Similar to what’s been said already, I’d say No it’s not useful if you want an absolute value for your bodyfat, but Yes it is useful if you’re going to track it every week.
I’ve got some very old Salter scales that give me Weight & Bodyfat % which I have absolutely no faith in with respect to the value itself but over the years I do think the trend is pretty accurate and corresponds to what I expect to see and other subjective measures.
So my question would be, what do you want to know the absolute value for? Curiosity, fine, if it comes out 5% different to your scales will it always be 5% or can you only rely on that one point in time?
These are my results this year, I’ve lost 4kg which seems to be almost entirely fat and that feels about right given I’m doing weights regularly and taking extra protein to try and protect muscle mass whilst watching my general intake.
Ps. Weight & Bodyfat are from the scales, all the other figures are just my calculations in Excel.
Pps. F*ck knows what was going on that first week, I pretty much ignore that.
My week of monitoring:
Hmm. Dont seem to be able to upload images
Over six days
Carbs 2279g 56%
Fats 526g 29%
Protein 628g 15%
I’m level at 86.7kgs this week, high normal/grade 1 hypertension
= 2727 kcal per day I reckon. Seems fair.
are you including alcohol kcals? midway between carb and fat
I was using MFP so assume it handles it?
So anyway, did some maths sitting in the pub re-planning my season as spring appears.
If 62kg is my lean body mass (0% BF) no wonder I’m not in the standard “healthy body weight range” for my height, which has an upper limit of 66kg iirc. At 67kg I’d have 7% bodyfat! 
At a bit below 87kg I’m 35% body fat by the scales I’ve used for five years, my goal this year is to get to 80 with around 25% bodyfat. Seems a tough target, but should help my blood pressure and performance.
Same here. 97kg at the mo. 178cm so by bmi is obese… my scales say 78kg fat free weight, so with 0% body fat I’m just at the top end of overweight bmi.
BMI doesnt work for a lot of people. The BMI range for me is 71 to 96kg. At 96 I was told I looked skinny. At 71 I would look fucking ridiculous.
yeah, I always thought it seems weird to link weight to height x height.
If anything , weight should be proportionate to volume, which is height x width x depth. If we are going to take one measurement, should probably cube it not square it.
I think this is why it doesn’t work well for kids, short people or giants.
76.7kg -1.0kg. Pleased with that as it was a relatively low exercise week. One of the few benefits of feeling some work stress. 
107.0kg & 34.6kg
Didn’t do any training mid-week for various reasons and, as usual, took that as a prompt to stuff my face instead, hence the above.
Must get back on the wagon this week with both cardio, weights sessions and diet.
Didn’t really manage to get back on 16/8 or do any exercise when avoiding running, so can’t be too surprised with getting up to 80kg over the last 4 weeks.
Going to get back on to 16/8 now, and having seen the sports therapist on Friday, I’ve got the green light to slowly return to running.
Blimey - he doesn’t quite look like I imagined when I saw the headline