Comment: Re:90% of max pulse? (Score 1) 434
Sorry but no way.
90-100% of your maximum heart rate will have you with tunnel vision within 1 minute and barfing your guts out within 4-5 mins; there is no way you could sustain 90% over a 5000m run.
Are you sure you where meassuring your actual maximum heart rate? How did you go about determining your maximum heart rate? 220-age is just a rule of thumb at age 28 I could go 202 on my monitor which is the maximum on that machine - it takes a drill instructor to get you to your actual maximum, not just where you feel like quitting.