Dirty Wknd Does Science: What Happens To FTP Results At Different Temperatures
Anyone who's ever done an FTP test, or multiple tests, will be able to tell you that it's not the most fun event they've ever done. Functional Threshold Power (FTP) is the amount of power you can sustainably hold for 20 mins (or an hour). Basically 95% off your maximum effort. So testing this means riding as hard as you possibly can for 20 minutes. Not fun!
Most people will do an FTP test at home on their Wahoo KICKR, at an indoor studio like Digme, or possibly out on the road with a power meter like an InfoCrank. Whatever your preferred method, it's always meant to be hard, and always (hopefully) rewarding, as you end up with some really useful data to shape your training. So when Jake "The Kid" Neale; club member, ride leader and official 'youngest person on any ride ever' asked a bunch of us to help with his dissertation, we all jumped at the chance to help our pal out. Then he told us we'd have to do 4 FTP tests. At varying temperatures between 8 and 35 degrees. And we weren't allowed any water during the tests. All the fun then...
Jake's MO was to find out how the different heat conditions would affect our power data (FTP). As willing lab rats, we were weighed before each test, put into the heat chamber for a 10 minute warm up, followed by a 20 minute FTP test. As well as analysing power output, Jake would be monitoring how much weight we lost in fluid during the tests. Which meant no water between the two weigh ins. Think about that next time you're on your turbo and complaining you don't have a fan! As part of the tests, we weren't allowed to know what the temperature in the chamber was until all 4 had been completed. We were also not allowed to have any data in front of us, or know what the results were, until after the 4th test, in case it influenced us. So no water AND no data? I know cyclists who could just about put up with the water thing, but no data? That is just too much!
Below is my data from all four tests, as well as my pre test notes (without knowing the stats) and then notes made whilst looking at the data. Without wanting to sound too GCN, this is Dirty Wknd doing science!
Test 1 - February 1st @ 12pm
Pre/During Test Notes: The first test was actually quite a nice temperature. After the 10 minute warm up I was sweating pretty hard though. At 5 minute intervals Jake would ask us to relay our perceived effort, body temperature and room temperature. The effort and temperature reading soon rose up to near max, and stayed there. I guessed that this was either the hottest, or second hottest test, but couldn't be sure. It was pretty weird not having any numbers to work to at first, but it was actually quite nice to just focus on feel and ride accordingly. All I had was jake occasionally saying "Come on, keep pushing" which didn't get really annoying at all!
- Heat chamber @ 25°
- Pre test weigh in = 78.2kg
- Post test weigh in = 77.8kg
- Weight lost = 400 grams
- Average Power = 286W
- Average Cadence = 101rpm
- Maximum Heart Rate = 189bpm
- Average Heart Rate =172bpm
Post Test Notes: Hindsight is wonderful, but I'm not surprised this was my best test. The nice warm conditions felt like riding in Mallorca (without the breeze) and the fact that it was the first one meant I probably pushed harder through nerves/showing off. It was also mid week, so I'd recovered a bit from the weekends activities. I wasn't sure what the weight loss meant, but 400 grams seemed quite a lot. I felt very dehydrated after the test, and was thirsty all day.
Test 2 - February 5th @ 9am
Pre/During Test Notes: First early test, and being a Monday morning I wasn't exactly thrilled to be doing a test. A bit worn out from racing and a long Sunday ride, I certainly felt a lot more laboured during the test. I did however feel a lot better about my hydration levels during this test. I think I was very dehydrated before the last test, so you can imagine how I felt after. Riding in the Vo2 mask is at best annoying and at worst really disgusting. It's very hard to breath, and your sweat collects in it. Not very nice, but you do sound like Bane, which is kind of cool.
- Heat chamber @ 15°
- Pre test weight in = 77.1kg
- Post test weigh in = 76.1kg
- Weight lost = 1kg
- Average Power = 270W
- Average Cadence = 106rpm
- Maximum Heart Rate = 180bpm
- Average Heart Rate = 165bpm
Post Test Notes: It's pretty clear from the difference in weight lost through fluid that I was really dehydrated in the previous test. Loosing 1kg of weight during 30 mins of hard exercise is pretty mad - think about that next time you're out on a 5 hour ride! Looking at my Heart rate it's a fair way off my maximum so either I wasn't trying (didn't feel like it) or I was a bit knackered from the weekend. Probably the latter.
Test 3 - February 13th @ 10:30am
Pre/During Test Notes: When I got back from getting changed, Jake had set my bike up in the chamber and kindly draped a towel over the bars - so I knew this one was going to hurt! It felt like a sauna walking into the chamber; think about doing an FTP test in a sauna. Let me tell you it's not pretty. It was a struggle to breath, especially through the mask, and the thick hot air and lack of water meant that I had a sore throat after the test. Legs felt ok though, very similar to the first test. Huge pool of sweat on the floor. Assumed I had lost about 5kg in fluid, but watching Jake clean it up made me a feel a lot better!
- Heat chamber @ 35°
- Pre test weigh in = 77.1kg
- Post test weigh in 76.4kg
- Weight lost = 700 grams
- Average power = 284W
- Average cadence = 101rpm
- Maximum Heart Rate = 189bpm
- Average Heart Rate = 173bpm
Post Test Notes: Surprised by the amount of weight lost - actually felt drained after the test so thought it would be more based on the temperature. Not surprised that power numbers are similar to the first test as legs felt pretty good. Also getting more used to riding on feel and getting better at holding a more steady power output. Felt a bit faint for the rest of the day, and no matter how much I drank, I was continuously thirsty. If nothing else, these tests are ensuring that I will definitely drink more on rides going forward.
Test 4 - February 19th @ 9am
Pre/During Test Notes: Jake had again laid out the towel on my bike, so I thought maybe I'd guessed the temperatures wrong, and this was another hot one. However, stepping into the chamber and immediately shivering, I realised it was a cruel joke. Thanks Jake, as if this wasn't cruel enough! As I'd only worn bib shorts or the first 3 tests, kit choice had to sadly remain the same. I won't be riding in just bib shorts on any cold spring days, it's not fun. After warming up, I felt this strange tingly sensation on my skin, and realised my body was trying to sweat. My Legs felt like utter garbage thanks to racing and the Hell of The Ashdown the day before. Despite sore legs and the cold, by the end of the 20 minute test I'd still pushed as hard as I physically could, and felt wiped afterwards. Was not excited to see my numbers after this test.
- Heat chamber @ 8°
- Pre test weigh in = 77.35kg
- Post test weigh in = 77.0kg
- Weight lost = 350 grams
- Average Power = 259W
- Average Cadence = 94rpm
- Max Heart Rate = 168bpm
- Average Heart Rate = 150bpm
Post Test Notes: Not impressive! Looking at max Heart rate, it's clear that I was shattered. RPM and power were much lower, but my perceived effort was still pretty high. What is most interesting was that I still lost 350grams in fluid despite the cold and the poor numbers. If you think about a long winter ride, where you never warm up and hardly touch your bottle, you're still dehydrating yourself. It's important to keep drinking regularly to keep your fluid levels up, even if you think you don't need to.
Conclusion:
When Jake asked me to take part in these tests, I thought it would be cool to help him out with his dissertation, but also to get a load of stats to play with. However it turned out to be a lot more interesting than I'd first thought, and I learnt an awful lot too. As a 'hot' person, I always thought I would suffer in hot weather, and therefore shied away from really hot days. Ss it turns out I'm not that bad at all - I just burn really easily. Maybe I can go on all those August cycling trips to the south of Spain after all!
What these test have illustrated to me is the importance of proper rest. Even just looking at my heart rate - no matter how hard I pushed in the final test, not getting above 168bpm is pretty damning. How can I expect my legs to do what I want them to if my heart isn't pumping as hard as when I'm rested. So along with drinking a lot more whilst out on rides (as well as before and after), I will be trying to rest properly between big efforts. I also learned that if Young Jake asks you to help out with something, it's best to politely decline...;)