HR and Lactate threshold

This could get a bit technical so if you’re not a HR afficionado, you may want to change threads.

My recent achilles injury has consigned me to doing a lot of time on the static bike in the gym. Now I find this very boring. So I have found myself doing two things 1) using a varying resistance (ie hills) type programme and 2) monitoring my HR very closely. I’d be interested if anyone can tell me what the results I’m finding tell me about my state of aerobic fitness/lactate threshold/lactate tolerance etc – and more importantly what to do about it. I embarked on this because I feel that whilst running I go up hills pretty OK but struggle to pick up speed immediately after the summit, and felt that this was the nearest thing to hill reps I could do!

Firstly some background on the specimen : male, age 44, Observed max HR when running (sprint at end of 2 miler) = 190. RHR ca 49. 10k PB =42:40 at avg HR =173 and I was close to this fitness when achilles blew out on me.

My static bike routine runs as follows (all at constant cadence)

1) 90 secs : power = 170 watts
2) 45secs : power = 184 watts
3) 45 secs power = 200 watts
4) 45 secs: power = 215 watts
5) 45 secs : power = 230 watts
6) 45 secs: power = 215 watts
7) 45 secs power = 200 watts
8) 45secs : power = 184 watts
9-14) repeat 3-8
15-20) repeat 9-14
21) 45 secs: power = 215 watts

set programme = 16:30 mins, I repeat this twice more with about 20secs break while I reset the bike computer – for a total effort time of about 50 mins. I’m not convinced about the numerical validity of the power output but it does imply a 25% swing peak/trough. In essence the programme is a bit like a Horwill alternating 10k run.

HR results:
My HR peaks during each cycle just after the max power leg: the first spike at about 152, then 158, rising progressively through 172 on the sixth and somewhere 176-180 on the 8th and 9th, by which time I can be near exhaustion, and I then cool down. During the troughs I find my HR falls back but by decreasing amounts – eg after the first peak it may drop back 10bpm but on the last only about 7. I’ve read that one’s cycling max HR is about 10bpm lower than one’s running HR so I feel that this workout is getting me close to my cycling max. Physiologically I am interpreting this as a session which runs on average above my lactate threshold and that I’m cycling anaerobically a lot of the time and the troughs are not sufficient to eliminate all the Lactic acid and this slowly accumulates as I approach the end. I feel this is in fact the way I run a 10k.

As an experiment the other day I set the programme I resistance level lower ie all the power settings wee 10% down and continued the programme for 75 minutes. I was hoping that my HR would approach a stable level whereby I was either not entering an anaerobic condition or was able to burn off an small LA accumulation in the easier legs. NOT SO. I found that my HR peaks continued to rise with each successive peak. I hit 172 on the 12th spike (cf the 6th at 10% higher power). I had to stop shortly after due to saddle soreness , but clearly my HR/energy use had not stabilised and thus my Lactic acid levels was gradually rising.

So amateur metabolists/sports scientists my questions:

1) Is my interpretation of the metabolism effects correct
2) If so, what is the correct training to a) raise my anaerobic threshold level and /or b)increase my ability to eliminate lactic acid during the recovery legs.
3) Any other comments

Thanks in advance. BTW feel a complete anorak having read the above and I guess its what the boredom of static bikes does for you!

Finally I see on the Europort TdF coverage cyclists talk about HR's as a % of lactate threshold, I think I understand why!


  • sth legs,

    IMHO (having done a fair bit of this in my day...) your time periods at each level are far too short - you're not giving the HR a chance to settle. Try 3-5 min instead of 45secs, then when you have a better idea of your AT you can warm up and settle at that wattage so you HR gradually rises to approx AT level (or just below) during about 1/2-3/4hr (as fitness progresses) - that will raise it nicely. But if you are new to cycling, you should be putting in miles before doing training this intense. Try watching the tour live for a couple of hours with HR at 135.
  • thanks Pantman - I'm sure you've explained the name somewhere..

    I'm not really planning on taking up cycling, just started by seeking an intense workout to substitute for running and settled on what seemed the program closest to intervals - I see it as a series of 600m's

    I'm sorry but 2 hrs slow burn in one spot would do my head in.....even if I was awtching, TdF, cricket....
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