Tri Talk Triathlon Podcast, Episode 55

How to nail your hydration strategy by determining your sweat rate, and how to use Jack Daniels’ running charts to set and achieve your running goals. All that, today on Tri Talk.

Welcome to Tri Talk, your podcast source for triathlon tips, training, news and more. New listeners to Tri Talk hail from Florida and South Africa. In Florida, I hope you had a good race at the Safety Harbor Multisport event. And in South Africa, a reminder that Ironman South Africa is just 4 months away. My goal at Tri Talk is to help you swim, bike, and run faster, to meet your personal triathlon goals. Whether you are an elite or amateur triathlete, we cover sprint distance to Ironman distance. Filling in for David Warden, I’m your host, Eric Schwartz, and this is Tri Talk Episode 55.


My name is Eric Schwartz, and I’ll be hosting the next 2 episodes of Tri Talk while David takes a break for the holidays. Today on Tri Talk we’ll be covering sweat rate and how to incorporate it into your own racing nutrition plan. You can determine your own sweat rate without a lab and I’ll tell you how. I’ll break down this topic in an easy to understand conversation. I’ll also tell you how you can use Jack Daniels’ VDOT formula to develop your own running goals and more specifically I’ll walk through how I’ve incorporated marathon training into an Ironman athlete’s training schedule.


Before we continue, I should probably introduce myself. My name is Eric Schwartz and David has bravely allowed me to guest host his show. I’m 38 and I’ve pretty much been racing all my life, all though I’ve cut back in the last two year. I’m originally from Indiana but I now live in Boulder, Colorado. I was a collegiate runner at Indiana University and took up multisport racing in college. After college I raced while I worked full time as accountant for 5 years. In 1998 I moved to Boulder and started racing full time. In 2004 I reached a long term goal of winning the Duathlon National Championships, and in that same year I finished 8th at Ironman Wisconsin. I’ve been coaching for 8 years as a member of Joe Friel’s Ultrafit and now as a member of TrainingBible Coaching. I also run the website, which covers daily triathlon and duathlon news and race results. Because I was known as a duathlete, at the end of the last podcast David set a lofty goal for me of being 2/3 of the host he is. Hopefully I can reach that goal. If you have questions for me you can reach me via email at or for coaching services you can check out my coaching website at


The first topic I’m going to tackle is sweat rate. It’s such an component of training but there are a lot of athletes that don’t really understand how it affects their racing. It goes well beyond hydrating for a race or a workout, and by the way, if your nutrition and fluid intake is good on a daily basis then you don’t need to do anything differently to hydrate for a race. You’re already well hydrated. But you better have a good hydration plan for your race.


My first memory of dehydration affecting my performance occurred in college. Our coach made us weigh in and out of practice so I knew my normal pre and post workout weights. On this day we were on the cross-country course and our workout included two 5ks. I felt good on the first one and did it in 16:30. On the second one I fell apart. I ran 17:30 and and it was very difficult. After the workout I was five pounds lighter than normal. Instead of worrying that my training was falling apart, I knew that my bad workout was probably a fluke related to poor hydration, salt intake, or something else unusual going on with my body that day. I really think multisport athletes should weigh themselves before and after a race. I have a feeling that a lot of bad performances could be attributed to dehydration – but without that measurement there’s no way to know.


So let’s get started.


Here’s how you can measure your sweat rate and stay on top of your hydration:


Before a long workout weigh yourself. Do the same thing after your workout. Every pound you’ve lost equals 16 ounces of fluid. To get an accurate measurement of weight loss you must weigh yourself with the exact same clothing before your workout and after your workout. Add in all of the fluids you drank during the ride. Measure your water bottles so you know how much they hold. I’ve found that 80% of the athletes I coach don’t know how much fluid they hold – they usually underestimate. I have athletes do this for workouts longer than 2 hours, but it’s a useful exercise to know how much you sweat on a 30 and 60 minute workout, especially if you focus on short distance races.


Here’s one other thing to consider. During the summer and during heavy training, especially in dry climates, you’ll lose a significant amount of fluid overnight. I’ve lost as much as 3 pounds overnight. If you start a long workout and don’t take into account this extra fluid loss it will affect your performance


Let’s move to a real example.


To use an example let’s do this for an athlete on a 3 hour workout. Beginning weight is 165 and ending weight is 162. By the way, actual weight isn’t important. We’re only concerned with the change in weight. That 3 pound weight loss represents 48 ounces of sweat. Between the pre and post workout weigh-ins, this athlete drank 4 bottles with 26 ounces of fluid and another 7 ounces of fluid out of a fifth bottle. That’s another 111 ounces of fluid intake that was lost through sweat. Over 3 hours this athlete sweated 159 ounces of fluid (48 ounces in weight loss plus 111 ounces of intake). That’s a sweat rate of 53 ounces per hour. That’s a higher than normal sweat rate, but I’ve worked with athletes that have lost even more than that.


Quick recap of the calculation – pounds in weight loss X 16 ounces per pound, plus total ounces of fluid intake, divided by total hours of training.


How do you use that information? Let’s say this athlete was doing a half ironman with an expected finish time of 5 hours. With a sweat rate of 53 ounces/hour this athlete would expect to lose 265 ounces of fluid during the race. That’s about 16 pounds! Studies have shown that losing 2% of body weight has no adverse affect on performance, and I know some athletes can lose a little more than that and still race well. For a 165 pound person a 2% weight loss equals 3.3 pounds. At 16 ounces per pound, that’s 53 ounces of a fluid deficit this person could have and still race well. We said his total sweat loss would be 265 ounces, so subtract 53 ounces from that and we get 212 ounces that he will need to replace over 5 hours. That’s approximately 42 ounces per hour, which is a little less than two big water bottles per hour.


Some athletes can easily take in large amounts of fluid during a workout while others would need to practice to achieve this level. Work on it in training before race day.


Let’s take it one step farther. After I have an athlete determine sweat rate, practice it, then execute the plan during a race, we evaluate the results.


After each race, especially a long race, an athlete should write down, among other things, their fluid intake during the race. If you have a scale at the race, which I highly recommend, (maybe some race directors can start providing them) you can also measure weight loss. From this evaluation you can determine how much the athlete was able to take in and how it correlated to race performance. If hydration was correct then race day is more likely to represent actual fitness.


Once you’ve established your hydration habits you need to monitor them in all workouts. If you don’t stay hydrated in training you won’t get the most out of your workouts and you won’t reach maximum fitness.


Moving on…


Some of the athletes I coach have specific running times they want to hit in the offseason or they want to train for a marathon while continuing to train for triathlons. How would you incorporate that into your training?


First, assuming you live in a cold climate, I think the winter is an excellent time to focus on running, especially if it is a weakness.


The starting point I use for running is Daniels’ Running Formula by Jack Daniels and I highly recommend you get this book.


Daniels uses something he calls the VDOT formula which is based on your current running fitness. Let’s say that right now you can run a 48 minute 10k. According to Daniels’ charts, if you can run a 48 minute 10k, you should be able to run a 5k in 23:09, a half marathon in 1:46, and a marathon in 3:40. In fact, if you know your fitness for one distance it will tell you what you could run for a 1500, mile, 3,000, 5k, 10k, 15k, 1/2 marathon, and marathon. I’ve found these charts to be very accurate. However, at the far ends of the chart – the mile and the marathon, the times won’t be accurate unless you’ve done the training for those distances, and if you’re heavily weighted toward fast twitch or slow twitch muscles, then the times at the opposite ends of the chart might not be realistic. But in the middle of the chart – 5k, 10k, and 1/2 marathon, they work very well. Most of the athletes I coach run 5ks, 10ks, and 1/2 marathons so the chart is really helpful to me as a coach and it’s helpful to an athlete for goal setting. The charts can also be used for determining workout paces for threshold runs, intervals, and repetitions, as defined by Daniels.


I’m going to walk through how I would train an athlete to run a 3:50 marathon while training for an Ironman for an athlete I’m coaching. Her goal is aggressive but a reachable goal. The marathon is in January and her Ironman isn’t until late 2008 so it fits in really well with her training and it gives her a good goal for the winter. She’s made great progress in her running over the last few years and brought her 10k time down to 52:17. According to Daniels’ VDOT charts she needs to be able to run a 50:03 10k and a 24:10 5k to reach that 3:50 marathon goal, and that’s assuming the endurance is there for a full marathon, which of course is the focus of the training. Those charts let me know that her goal is realistic but there’s still work to be done.


I’ve got a good chart of her running results over several years and her 10 mile race time, done on the same course, takes big drops so I know we haven’t reached her peak running fitness. In 2006 she ran a 10 miler in 1:28, which was a 10 minute PR, and 1 year later she cut another 4 minutes off that time.


A 3:50 marathon goal is an 8:46 mile pace so she has to be prepared to do longer efforts at that pace so we know it is realistic for race day. I’m also having her do shorter tempo runs at a pace faster than that – for example a 5 mile tempo run at 8:20 pace. The faster workouts should improve her fitness and make her goal marathon pace seem easier. In total she’s doing 4 runs per week.


She’s still training on the bike and the swim but running is her focus until the marathon is over. I’ve cut back her swimming the most because that’s going to have the smallest impact on her Ironman. A good training week is 8-10 hours total and she’s swimming once or twice a week. She’s on the bike twice a week. My belief is that with cycling, during the offseason when time is limited and the weather is bad, frequency is less important then it would be for running and swimming. But because frequency drops, the quality of those workouts needs to be higher. With two workouts one should be a longer ride on the weekend and the other one is a shorter, more intense effort during the week. If the weekend ride is outside it’s in the 2-3 hour range with the main goal being endurance and maintaining those cycling muscles. If you bike I’m sure you’ve notice your muscles decrease in size and that’s not such a good feeling, at least for a guy, when you know you’ve got to get them back. If the weekend ride is on the trainer I like to do a 1.5 to 2 hour ride, sometimes longer, with a warmup, drills, and some kind of set to mix up the boredom. Here’s a sample set to include on the trainer during base season:


1:45 ride with warmup, drills, 2X1.5 minute fast (optional), 2 minute recoveries, 1X20 minutes in zone 3, 5 minutes easy, 1X10 minutes at 100+ cadence, 5 minutes easy, 5 minutes standing, 5 minutes easy riding, 15 minutes zone 3.


This workout accomplishes a couple things – it works on technique, base building, and endurance, while breaking the monotony. For an athlete with a CompuTrainer, which is a great tool, I like to include climbing. With a CompuTrainer you can set it to climb at a specific grade – it probably goes about 15%. An athlete will get more bang for their buck if they can simulate climbing with their limited time.


So that’s how I’ve Incorporated marathon training into her Ironman training using Daniels’ book, but his VDOT formula will work for any running specific goal and it’s a great book for helping you design some of your own running workouts.


That’s all for episode 55. I’ll be back in a couple of weeks with episode 56 of Tri Talk. I’ll see you next time!