...is rarely as fast. Your lungs are burning and sweat drips down your ass...
(the above words are to be sung out loud to the tune of: "Summer Lovin" from the musical Grease - I dare you!!)
Ok my warped sense of humour aside, running in hot/humid conditions can deplete your energy levels faster than unnecessary apps can drain the charge from your smart phone. And it can be even more annoying.
Dealing with heat and humidity puts a large extra energy use load on your body. Not to mention the loss of fluids through sweat.
Let's be clear here too - it's not just about running in the Summer months, although that's when it's at it's most obvious here in the Northern Hemisphere (I live in the UK). This same additional load can happen suddenly in early Spring and is often the cause of poor performance for athletes running an early Spring marathon like Boston, Paris or London. As an un-seasonally warm race day can leave your body reeling.
It takes time to acclimatise to heat. At least a couple of weeks and if you don't run often - probably more like 4 weeks.
So when you've been used to running in very modest temperatures through the winter months - to suddenly be hit with what is equivalent of a balmy Summer afternoon - you've got little chance of dealing with that extra heat load efficiently. The sensible thing to do in these conditions is just to slow down and put your new marathon PB on hold until next time.
This phenomenon incidentally is why I much prefer an Autumn marathon. As at least then you would have trained through the Summer months and experienced running in the heat. So an unseasonably warm Autumn day will not be such a shock to the system.
It's not all bad news though. There is some research that indicates that you can achieve quicker and greater fitness gains by training in the heat - but that's probably best saved for another blog post. For now let's concentrate on giving you valuable information for making the most of your Summer Running...
Top Tips for running in the heat:
Lightweight technical clothing
I'm old enough and have been running long enough to remember the times before "technical' clothing was a thing. Back then cotton was the main t-shirt fabric and wearing a cotton t-shirt to run in the heat sucks big time.
Cotton gets soaked with sweat and doesn't dry quickly, it clings to you, can rub/chafe and it stretches - which could reveal parts of your anatomy that you'd rather keep covered in public.
Modern technical fabrics are far more comfortable to wear, they're lighter, more durable - but most of all they wick the sweat away from your skin and dry very quickly.
Another thing to consider is that some lighter colours (especially shorts) tend to show sweat stains more than darker ones. This can sometimes make you look like you've had a bladder control malfunction.
Don't run with a bottle in your hand - it has a negative impact on your running form. Far better to run with a bottle belt or a hydration vest/back-pack.
Avoid maximum temperatures - run early
Try not to run at mid-day or early afternoon when temperatures usually peak. Some runners prefer to run in the evening, but I much prefer to get up early and get my runs done at the start of the day. It's much quieter and cooler then. Especially if you intend to run on a tarmac road or footpath. Because those surfaces absorb the heat of the sun during the day and radiate it back out in the evening/night. So it will be much cooler come morning.
If you get out early enough, there's less need to apply sunscreen to exposed skin. As you shouldn't be in the strong sun long enough to burn. That said, it's always better to play safe and apply some - just in case you have a mishap and end up walking back or taking longer than you expected, because you took a wrong turn and got lost (both of which have happened to me in the past). Make sure your sunscreen is water-proof, so that your sweat doesn't wash it off.
Choose shaded routes
If you can plan running routes that are shaded and ideally for a couple of added bonuses - alongside some water (sea/river/stream/lake/pond) where there is also a breeze. A personal favourite of mine is to run along my local canal.
As I'm follicully challenged, I always wear a peaked cap in the Summer months. It stops my scalp getting sun-burnt and protects my eyes from bright light (and sweat from dripping in them too).
However, if you have a fulsome head of hair you may prefer to wear a visor. This will help keep your head cooler.
Squinting in bright sunshine will make the muscles of your face work harder than they need to and could also lead to a headache. Not something you need to contend with whilst training. Another advantage I find is that they stop bugs flying into your eyeballs and reduce the amount of pollen getting in there too - a big bonus if you're a hay-fever sufferer like me.