When to run while training for climbing and working?

Brian Abram wrote:The best theory I've seen is that sprints induce a physiological response that causes muscle to be preserved more than normal while burning fat as the primary fuel source (all exercise actually causes muscle to be burned for energy to some degree (eat protein after all exercise)). More total calories may not be burned in sprint training, but those that are tend to come from fat, resulting in better fat loss.

Fat is not the primary fuel source in sprinting whatsoever. Sprinting is an anaerobic exercise and therefore uses glycolysis as a substrate--with the aerobic system kicking in to help out with ATP production to some degree.

The small amounts of glucose found in skeletal muscle is not typically tapped into for fuel, either, unless you are doing hardcore endurance events. Protein plays a very minor role in fuel metabolism.

Eating carbohydrate after exercise (not protein) will be far more conducive to sparing muscle breakdown later.

Brian Abram wrote:You may burn more calories going for a 45 minute jog, but many of those additional calories will come from burning off muscle tissue - no bueno.

Totally not true. If you really believe that your blood glucose, liver and muscle glycogen stores can actually be almost totally depleted within only 45 minutes of moderate aerobic intensity exercise, I don't know what kind of books you've been reading.

To the OP: as someone who has trained others for many years, I would recommend you experiment with running at different times of day/days of the week and see where in your schedule it works best for YOU. Who cares what works for other people. The method that is the most successful is the one YOU will stick to.

I hear ya. Like I said, I haven't seen a really good explanation for why short sprints result in more consistent fat loss than moderately long, slow jogging. All I know is consistently seeing that conclusion in studies.

exrx.net/ExInfo/HIIT.html

Read the 3rd paragraph. I don't know what I'm talking about whatsoever, and that's why I post links that sound authoritative.

ampedtraining.com/fat-loss/…

A pretty even handed explanation that seems pretty informed. Apparently the idea that glucose and glycogen stores have to be depleted for the body to even begin to use fat or muscle as fuel is not really accurate. If you wanna read just a little bit of that last one, read the 4 paragraphs above the header "Criticisms and Potential Problems." (Read the criticisms, too. They're valid, though all they basically say is that long, slow training might actually be just as good as intervals... Not exactly a huge endorsement) The gist of what he's saying appears to me to be that high intensity workouts cause your muscle tissues (specifically) to begin storing glycogen while oxidizing fat as their major fuel source, and that this occurs after your workout.

What I get from this is that looking at what fuels your body uses during the actual 30 seconds or 45 minutes of activity is an overly simplistic way of seeing what's actually going to happen in your body, and that fuel metabolism doesn't end with the end of your workout. Apparently how hard you worked out dramatically changes how your body copes and exactly what it begins to metabolize in the minutes and hours after exercise, and when it's all taken as a whole, the results appear to be vastly different in relevant, measurable ways. You cannot talk about metabolism and its relation to 4 minutes of sprints or 45 minutes of running and discuss glycolysis or fat oxidation without talking about what happens post workout. Sprints may indeed not utilize a bit of fat for their 30 seconds of work, but it doesn't matter because they managed to induce changes in your metabolism that will last for a long while. Sprints and long slow endurance training each have different effects. Apparently, one of those differences, in the end, is that more fat winds up getting burned if you do high intensity intervals than if you go relatively long and slow (insert long and slow jab here). This appears to be due to the type of muscle stimulation that all-out efforts give that you don't get from long slow running.

From that second article, I guess what my first quote should have said is that sprints stimulate metabolism of fat as the primary fuel source in your muscle tissue, post exercise, while glucose gets stored away.

My second quoted text should have said something like "you may burn more calories going for a 45 minute jog, but most of those calories will come from glycogen, of which your body normally has a pretty large supply (from all those carbs you're killing yourself with). However, in addition, a relatively high number of calories will actually come from metabolizing muscle, with relatively little tapping into fat stores during or post workout compared to what would have happened if your muscles had experienced high intensity sprint stimulation. This is apparently due to the massive amount of glycogen available during long slow running and the lack of stimulation in your muscles to get them to convert to using fatty acids... again, post exercise."

By all means, go and run for hours every week. It certainly won't kill you, and it will certainly increase your cardiorespiratory endurance and make you better at jogging really far. Many people start enjoying it for its own sake. I'm full of crap, too, as personally I'm far from being a competitive runner, never having gotten under a 19 minute 5k. What I am just saying is that if the OP is pressed for time, and there is increasing evidence that sprints are just as good as LSD training for endurance, fat loss and eveything else except maybe the psychological component of continuing to run and run and run, then it's something he might consider.

Jogging for 45 mins wasn't what I was talking about in my post. I was talking about running as in 7 min per mile pace or faster for 45 mins or what ever pace will put you at your peak cardio output(obviously diffrent per individual). I could see how it would be possible to burn more fat from doing 15 mins of interval training then jogging but at the same time you shouldn't do sprints as often because of the amount of muscle tearing involved. Sprints are like lifting weights sort of like maxing out on bench press, an all out effort. Sprints tear your muscles just like lifting weights do, there for you need more time to properly recover from them than just running. So you would be working out on a smaller frequency which doesn’t take a Dr. to tell you isn't what you want if you are trying to lose weight and boost your metabo.

Brian Abram wrote:I hear ya. Like I said, I haven't seen a really good explanation for why short sprints result in more consistent fat loss than moderately long, slow jogging.

That is because they (researchers) don't know.

Brian Abram wrote:Apparently the idea that glucose and glycogen stores have to be depleted for the body to even begin to use fat or muscle as fuel is not really accurate.

The body uses fat preferentially before it uses glucose or glycogen. Muscle is truly a last resort for the most part, so I stand by my statement that you have to be very low on carbs to start doing any serious protein damage.

Brian Abram wrote:The gist of what he's saying appears to me to be that high intensity workouts cause your muscle tissues (specifically) to begin storing glycogen while oxidizing fat as their major fuel source, and that this occurs after your workout. What I get from this is that ... fuel metabolism doesn't end with the end of your workout.

After a workout (and thus at rest) the muscle's main fuel source is fat. Also, yes, the muscle will begin to try to replenish depleted glycogen stores. That's standard stuff there.

Brian, these kinds of theories aren't new (well, okay, maybe they are new to you). Your link was really interesting (thanks!), but the real facts are that this guy is still hypothesizing, and exercise physiologists are still researching as to the "why."

Brian Abram wrote:"you may burn more calories going for a 45 minute jog ... in addition, a relatively high number of calories will actually come from metabolizing muscle, with relatively little tapping into fat stores during or post workout compared to what would have happened if your muscles had experienced high intensity sprint stimulation.

No, 45 minutes is not really a long enough timeframe to begin burning a "significant" number of calories from muscle--not at all. Think more like over two hours. And you better believe 45 minutes of cardio will tap into your fat stores--both during and after! If not for that fat, you won't be running no 45 minutes, son!

Also, this part you stated: "This is apparently due to the massive amount of glycogen available during long slow running and the lack of stimulation in your muscles to get them to convert to using fatty acids... again, post exercise" is...well...kinda nonsense.

Could you elaborate on the nonsense? In a PM even, if you want. I really am curious and want to know more. Reading carefully through the section headed "Nutrient partitioning" in my second link, that seems to be exactly what he's saying (though my wording could have been better)...that we have a ton of glycogen for aerobic efforts, that there is not much stimulation to make your muscles use much fat during aerobic exercise until you deplete glycogen, but that you can reach that point quickly with anaerobic exercise.

Of course, I could be reading it wrong or he may be wrong.

Hey Sunder,

Another thing that I think helps a lot with staying motivated is keeping a blog of your workouts! Just get one on Blogger and spew your workouts on it. Include what you did, how you felt, and what you could improve on. This helps me a lot with ultras I run. It's like a coach in a way.

Also might want to think about using a web site that can track it all for you. those are cool too. attackpoint.org/ is a good one.

Spring is here! Have fun!

Ian F. wrote: Maybe think of sprinting differently. I have employed this style, mainly because, I can't follow any regime, so I like to break things up all the time. But, I run slow (jog) for a bit, then walk a short distance, and prep for a relatively fast run, for as long as my legs can handle, (1/2 mile to mile), then walk until I feel good again, and do it again. Each time the fast run get's shorter, but it makes a bigger difference to me than just jogging the same route all the time. But, the sprint doesn't need to be a 100yard dash, just bump up your speed, and go for as long as you can.

This is a good technique to mix in maybe one day a week in your program, they call it 'interval training' and it helps build endurance and to develop speed.

With all the advise the a 45 min run doesn't really burn fat and doesn't help you much... I should just stop running then? I could sleep during my lunch breaks instead.