If you 're using a powermeter .
You watch the difference , you could be sitting in a doing 200 watts and a 130 heart rate , but if you 're up front fighting the wind , you could be at 400 watts and 160 - 170 heart rate .
If you 're using a powermeter and you watch the difference , you could be sitting in a doing 200 watts and a 130 heart rate , but if you 're up front fighting the wind , you could be at 400 watts and 160 - 170 heart rate .