Great thinking but before you use your average HR from these races to estimate your AT, there are a few things to consider.

In our book we recommend stand up paddle race athletes determine their training heart rate zones with a much shorter AT test . The problem with using a longer test, such as a 1 hour race performance,  is that inexperienced SUP racers and beginner athletes cannot push hard enough for the duration of the race. It is very common for beginner athletes to go out way too hard, blow up midway through the race, and then pick it up at the end of the race if they have anything left in the tank. These fluctuations in effort will causes errors in AT estimation, and as a general rule, cause an UNDERESTIMATION of AT and subsequent errors in determining their heart rate training zones.

Conversely, experienced paddle racers are able to pace themselves and push through an hour long AT test or race. For experienced athletes, the odds are good that they will be able to hold very close to their true AT throughout that entire 60 minutes.

It sounds like you definitely fall into the high level of experience (NOTE: Larry’s email was longer than noted above)   Take a look at your Garmin readings. If you are able to pace yourself through the races without huge spikes in your HR and you do not blow up at any time during the race, it is likely that your AT will be very close to your average that you were able to hold during these shorter races.   As a general rule, you can expect your AT  to be slightly higher than the average heart rate.

TECHNICAL NOTE: when calculating your average, you should consider eliminating the first 3-5 minutes of your race. Your heart rate may be either very high (nervous energy) or low (ramping up over the first 3-5 minutes of the race). Either way a spurious heart rate reading measurement in the first few minutes of the paddle race skew your true overall average by a few beats.

Based on the information you provided us a good estimate would be 166 for an anaerobic threshold based on last years races.  To get an even better idea of your AT, go back and take a look at your average HR for the  middle 3-4 miles of each race as this may be even closer to your true AT.

Before we let you go, one more thing to remember is that the numbers you provided us reflect your AT during the racing season when you  were at your highest level of fitness.  If you took an off season and are just starting back up odds are good your AT will have dropped a little. Remember: less is more when you are endurance training. It is always a safe bet to under do it a little when building your base then overdoing it. We recommend adjust all your SUP  heart rate training zones down by 5 beats during the first 4-6 weeks of training until you regain some base and fitness.

Another option is to perform an early season AT test  or race and get your training zones dialed in.

It is good to hear that you are feeling the direct benefits of not hammering all of your workouts.  There are racers and there are trainers.  Do  you want to win the Tuesday paddle or the race on the weekend? Odds are good you can’t do both so pick one or the other. As you have learned, it does not always have to hurt like hell in order to make you faster and it is nice to not always be suffering during a workout that you love doing.

Roch