1. Glasses demonstrate high school rules of physics

Most notably that hot air rises. This becomes apparent when you lie down to stretch at the end of a workout and the heat rising off of your face condenses into steam on your lenses, rendering you blind. Still, it’s nice to know that your science teacher wasn’t lying to you.

2. High knees are the enemy

Doing such a high-intensity exercise means you could really do with using all of your concentration to just. Keep. Breathing.

Yet you end up getting distracted by the rhythmic bash of your frames jumping up and down on your face, along with the dizzying effect of bouncing lenses. The same applies for burpees, tuck jumps, sprints and basically anything that means you have to battle gravity.

3. Urgh, weather. All weather

You’re heading outside for a run – do you wear glasses or sunglasses? Check all the weather apps you want, your decision will probably be wrong.

Leave you sunglasses at home and you’ll be left squinting and half-blinded by furious sunshine; put them on and you’ll be wading through sun-less, murky streets looking like some kind of wannabe rock star. As for rain? Don’t even get us started.

4. Your nose can sweat

Who knew? Well, glasses-wearers did. We make this discovery after just a few minutes of working out, our glasses will begin to slowly slide further and further towards our nostrils, impairing both sight and breathing. So then you have to start pushing them back up with such a frequency it looks like you’ve developed some kind of nervous twitch – particularly perilous when you forget that you’re holding dumbbells.

5. Lens sweat waterfalls are a thing

They’re a pretty special occurrence, which usually take place when you’ve gone from doing some kind of HIIT exercise, quickly followed by doing something like holding a plank. The sweat from your head cascades downwards, hitting the eye-side of your glasses and running down the lenses. It’s not ideal, but at least it’s cheaper than paying out on a trip to Niagara Falls.

6. Glasses can make you a target for gym instructors

On more than one occasion I have had a class instructor proclaim (loudly on their headset): “If this ladies’ glasses haven’t steamed up by the end of this class, then you’re not working hard enough”. Cue pleading looks from all fellow participants.

7. When you finally get fed up and take the glasses off…

Yes! You’re free! What a relief. Oh, except that now you can’t see anything at all. What exercise are you meant to be doing now? Where are you? OK, maybe you should put your glasses back on. Where did you throw them? And what was that loud crunch under your foot?