Heading high to peak at the Tour de France: The theory vs reality

The altitude camp is a staple of every self-respecting professional cycling team’s annual training programme, especially when the mountains of the Tour de France home into view. It’s an oft-ridden path of altitude camp, Critérium du Dauphiné, another hit at altitude before descending for La Grande Boucle. The aim is to train high in search of the highest step on the Parisian podium. It’s textbook sport science. But how does the theory play out on the roads of France? 

Here, Rouleur brings together James Barber, lead performance specialist at London’s The Altitude Centre, and WorldTour rider Luke Durbridge to marry the ideal with the real. Barber, a fine athlete himself (his maiden marathon took just 2:39hrs), has helped the likes of triathlete Alistair Brownlee, heavyweight boxer Anthony Joshua and countless Premier League footballers reach peak performance. Australian Durbridge, 32, is in his 12th season with Jayco Alula. He’s undertaken domestique duties at the Tour de France in eight of the nine past seasons, finishing six, and is set to be there again when the Tour starts in Bilbao on July 1, 2023. Both provide a fascinating insight into the impact of altitude on performance as the countdown to the Tour begins…

Luke, we catch up with you in mid-to-late May. We hear you’re just off to altitude camp?

THE RIDER: LUKE DURBRIDGE (LD) I am, albeit it’s a two-week camp in Andorra where I live. Sometimes we’ll have a camp at Pic Maia, which is the highest hotel in Andorra [and the Pyrenees at 2,408m]; sometimes we’ll be a little lower at Bordes d’Envalira, which is around 2,000m; and my place is in Soldeu, which is around 1,800m. So there’s a variety of options in terms of altitude exposure. At this camp, I’ll be at home but joining the team at Pic Maia.

What are the main physiological adaptations of an altitude training camp for the Tour de France rider?

THE SCIENTIST: JAMES BARBER (JB) The headline is increased red blood cell count. These are the small cells in our blood that carry oxygen. Specifically, oxygen binds to haemoglobin, a protein that’s found on red blood cells. So, more red blood cells, more haemoglobin, more oxygen being carried to the working muscles and importantly to the brain. Ultimately, that’ll allow the rider to ride at a higher power for longer and also assist with recovery after a hard effort.

Mind you, it’s all well and good delivering more oxygen to the muscles, but we have to be able to use it when it gets there, otherwise it’ll just flow back round the body. With altitude training, we become more efficient at extracting oxygen from the blood and then using it. That’s due to an increase in myoglobin content (the protein in which we store oxygen in the muscle) and mitochondrial density and efficiency (mitochondria are the organelles in which we use oxygen to produce energy). That means we can produce energy ‘aerobically’ at higher intensities, meaning a higher power output becomes more sustainable for longer.

How much benefit can a rider gain from a two week camp? And how should training workload vary over the camp?

THE SCIENTIST: JB We know that haematocrit increases by around 1% for every 100 hours spent at altitude, so there’s a lot that can be gained in two or three weeks. Here, we’re not just talking performance, but also acclimation. There are some big mountains early on this year’s Tour de France and, on those stages, altitude can impact performance. 

By spending lots of time at altitude you can elicit the blood-based adaptations mentioned, but periodically descending for the harder rides might help the quality of certain sessions. After all, if you want to ride at 500 watts in the Tour de France, you need to ride at 500 watts at some point in training! That’s again why we’re seeing more and more riders make use of simulated altitude. They can sleep in an altitude tent overnight and maybe have a nap in there during the day. They can then do their hard intervals at sea level and then recovery and endurance rides on the turbo at simulated altitude to help manage training load and optimise adaptation.

THE RIDER: LD Over a two week camp, we might keep it really low for three or four days as it’s about exposing yourself to altitude – no efforts, no pushing your body and making sure you’re keeping an eye on your heart rate. Overdo it early on and, coupled with low oxygen when recovering at the hotel, it really hits you after the fifth day.

You then step into the first block proper, which is zone two work. For me, that’s around 130 to 160 beats per minute. That means climbing. The second main block of camp is focused on more explosive efforts between two and 20 minutes. That’s your race sharpeners. You’d then just cruise back to the hotel and use the altitude as added stress when recovering after those intensive efforts. We’d also do efforts lower down the mountain for more stress on the muscles.

The problem with camp is that it’s difficult when you have five or so guys and they’re all vying for Tour selection, so racing each other’s a common scenario. But with experience, you know that it’s the rider at the end of the camp, coming out with the best form heading into the race, that will be selected over the guy who wins the first sprint back to the hotel on the first day. 

How can you monitor physiological adaptation on an altitude camp?

THE SCIENTIST: JB The best marker of performance is performance, so either formal (heart rate, power data, ect.) or informal (rider feedback) performance monitoring would be best. However, it would also make sense to monitor blood for haemoglobin mass.

THE RIDER: LD The coaches keep an eye on our power and heart-rate data. We also measure oxygen saturation levels in the blood. You just clip the tool to your finger; in fact, I have one in my bag. It’s useful if you’re staying at around 2,500m. But as a team, we don’t focus too much on blood tests.

Should, or does, nutrition change when training at altitude?

THE SCIENTIST: JB There isn’t solid evidence behind this but probably. Iron status is important to get right, but for an endurance athlete they should be monitoring iron as standard, and any athlete with low iron should consider an iron supplement before and during altitude exposure. Metabolism may also change so there’s a slight increase in reliance on carbohydrates for fuel, so overall diet composition may change slightly. 

Then, it’s a case of optimising response to training. That means avoiding sickness and injury, which are unfortunately common at altitude, not because of altitude but because athletes go on camp and suddenly increase training load exponentially! Glutamine and vitamin C supplementation could be useful.

THE RIDER: LD We don’t necessarily take extra supplements. But what I do find is that at altitude camp you have support, so you can fuel better. It’s quite difficult to consume 120g of carbohydrate an hour while you’re training solo – you have to stop at service stations and fuel up – but when you have a support car following you, you have ready access to all the bars, gels and blocks you need.

Back at the hotel, you’re looked after by the soigneur or chef. And generally we have a nutritionist who’ll then monitor weight, take skinfolds and make sure that everyone’s as lean and strong as possible for the next goal. 

Returning to that 120g an hour, that’s probably the biggest change in the last couple of years. The amount that we consume now compared to the start of my career is night and day, and I put that down to why the racing is so much faster now. Riders are just not running out of fuel. Mind you, you must train your gut. That’s why we’ll have sessions where we’ll focus on high calorie intake. These tend to be sessions focused on intensity. They’re not easy to do but they are worth it.

So, Luke will train at altitude and then come down for the Critérium du Dauphiné that starts on June 4, 2023. How long will the physiological benefits last?

THE SCIENTIST: JB Peak performance from an altitude camp can come anywhere between one to 14 days post-altitude. 

THE RIDER: LD It’s a funny one but when I come down from altitude, the first few days I feel great and then for many days afterwards I feel really sluggish. Come the 10-day mark, I’m starting to feel good again.  

Riders are seemingly spending ever-greater blocks of time at altitude. For instance, we interviewed Jumbo Visma’s performance coach Mathieu Heijboer, who told us that Primož Roglič spends weeks at a time training at altitude in Tignes, France. “It’s about the accumulation of altitude,” he said. Does this hold up to scrutiny?

THE SCIENTIST: JB Almost certainly. Although the research hasn’t necessarily caught up, we are working with more and more athletes on their long-term periodisation of altitude training. Each camp may have a different purpose, which dictates where they go and what they do, as well as use of simulated altitude between camps. 

There does seem to be benefits in accumulating repeated exposures to altitude, in that the initial lag/acclimatisation time appears to reduce with repeated exposures (meaning you can train fully, earlier into the camp), and some research suggests that athletes may be more likely to respond to altitude training after repeated exposures.

THE RIDER: LD We’re certainly seeing a trend of more riders spending more time at altitude but, for me, it depends on what engine you have. I’m a diesel and, for the past few seasons, I’d trained heavily at altitude before the spring Classics and hadn’t felt as sharp. If I’m constantly riding long climbs at high altitudes, it can make a big guy like me quite slow. That’s not great for the short, sharp efforts of the Classics.

So this year, I scrapped all altitude before the Classics and trained further south in Spain. I rode a lot of flats with short, sharp climbs and, while I didn’t have a spectacular campaign, my numbers were much better. It goes to show that altitude doesn’t always work. Then again, you’ll have guys who’ll come straight down and win a Classic.

After the Classics, I increased altitude exposure due to my role going forward, which is as a domestique for Simon Yates or Michael Mathews. It’s less about those short, sharp efforts and more about sustained, zone-two stuff where I’m pushing winds and looking after my leaders. You don’t need to be so explosive.

The Critérium du Dauphiné finishes on June 11, 2023. The Tour de France starts July 1, 2023. Ideally, is it a return to altitude after the Dauphiné?

THE SCIENTIST: JB It’s highly individual. Ultimately, riders and their coaches and sport scientists will be looking to peak for specific make-or-break stages within the Tour de France, so they’ll be looking to time all of their training, not just altitude, around those. 

THE RIDER: LD Yes, but it might only be for around five days. In the past I’ve gone straight from the Dauphiné to altitude but just to recover rather than train. I’ll then head lower to sharpen up for the Tour. I prefer the Dauphiné over the Tour du Suisse because you have a longer period to work on something specific if needed. That might be losing a little weight or more time trialling. At the Tour du Suisse, you sort of recover and then head to the Tour.

A climber might have a different opinion or schedule. Usually, my job’s really important for the first 10 days of the Tour de France because it’s usually relatively flat. It’s more about holding position like the Classics. Granted, it’s a little more mountainous this year with the start in the Basque region. But generally, I need to be sharp to get my GC guy through the early stages. I know in the past, Simon Yates has dropped from altitude straight to the Tour because even if he feels a bit sh*t in the first week, it doesn’t really matter that much if he can then storm it from the second week. In short, no-one’s ever asked me to step off [Tadej] Pogačar at 2,000m!

Finally Luke, what are your overall views on altitude training?

THE RIDER: LD I just think there are so many variables that it’s really hard to say but it’s 100% impossible to compare year on year. One year, you might have two weeks of altitude, drop into a Grand Tour and have a good race. But is that because of altitude? Maybe. Or it might be because it’s your second Grand Tour of the season and your engine’s larger than 12 months before. Also, a year earlier you might have missed a block of training due to sickness. It’s really hard to quantify.

What’s clearer to me is the ‘camp effect’. At camp, you eat, sleep and train. You recover better and sleep better. You have all these people around you, looking after you. It’s just more conducive to peak performance than at home.