Distance V's Speed

[Colbaker]

Hi all,

I have an eliptical trainer and am working on losing some of my excessive amounts of lard, Problem is i struggle with time due to kids and work, I don't really have time for long workouts on the trainer so i i have been upping my speed in the 15 - 25 minutes a day i am able to use it.

In you opinion is speed/intensity of the exercise better at weight loss than a slower speed but over a larger time frame? (obviously a faster speed over a long time is better), for instance would it be better for me to do 15 minutes at 5kmh or 25 minutes at 3.5kmh?

 

[tl45]

From what I've been advised it's the more moderate, longer gentle exercise where the body will use fat as energy supply. As you up the intensity level (and heart rate) you'll start burning carbs as the body can't turn the fat into energy quickly enough.

So I'd say lower speed and longer sessions. You can pick up basic heart rate monitor watches pretty cheaply and along with some info off the web you can work out approx. heart rate zones so you have a better idea what level you're actually training at.

 

[Fuggan]

There are different schools of thoughts on "what's best". It can get very complicated, so as a general rule, if you don't have time for long workouts, do some intervals like..

90 seconds steady, 30 seconds flat out.

And repeat that for 10-15 minutes or so.

 

[Jonny69]

From what I've been advised it's the more moderate, longer gentle exercise where the body will use fat as energy supply. As you up the intensity level (and heart rate) you'll start burning carbs as the body can't turn the fat into energy quickly enough.

And this is my experience of how it works too.

I'm quite fit because I ride to work every day and run regularly. I eat a lot as a result and my bodyfat stays fairly constant. If I up the intensity, I have to eat more to keep up, I get stronger and put on a bit of muscle mass, but my bodyfat level stays roughly the same. When I train for a long event like a triathlon or a marathon I also have to eat more to keep up, but I start to shed bodyfat and my muscle mass changes slightly from bulky strong muscle to leaner muscle.

You'll shed a bit by increasing the intensity but only to a point - probably because by upping the intensity you'll also increase the calorie burn. Then you'll have to look at increasing the duration if you really want to lose a lot. My advice would be, when you're ready, load up the iPod and switch from the cross trainer to running outside in the evening. It's the ideal time to start now because the evenings are nice and light and warm.

 

[Begbie]

If your main goal is fat loss, HIIT (Interval training if your not fit enough for HIIT) is well worth doing if your short on time. It no end improves my V02 max when doing so.

 

[mrthingyx]

From what I've been advised it's the more moderate, longer gentle exercise where the body will use fat as energy supply. As you up the intensity level (and heart rate) you'll start burning carbs as the body can't turn the fat into energy quickly enough.

So I'd say lower speed and longer sessions. You can pick up basic heart rate monitor watches pretty cheaply and along with some info off the web you can work out approx. heart rate zones so you have a better idea what level you're actually training at.

Not quite.

The body views energy stores in terms of what is easy for it to use: fat is very difficult (creating glucose out of triglyceride requires a fair old transformation), but glycogen is very easy. So it will go for glycogen first, regardless of the intensity of the exercise.

The principle behind high intensity interval training and its effect on fat loss is (very generally speaking) that it quickly exhausts the existing glycogen stores and - depending on one's diet - requires the body to regenerate glycogen stores from fat while 'resting'. So the whole exercise regime can be truncated into a much shorter period of time, rather than for slow, steady-state cardio.

So the answer to your question is 'speed', but should actually be 'intensity'.

Load up a smartphone HIIT app and have some fun.

 

[arknor]

I thought different intensities use different energy stores?

I read for cycling there's a difference between high cadence and low cadence but in a harder gearing

Physiology

Low-cadence cycling requires us to push harder on the pedals, but what does this mean at the level of our leg muscles? To generate that higher force contraction, your leg muscles must recruit more fast-twitch muscle fibers v. slow-twitch fibers.

Slow-Twitch Fibers:

Primarily burn fat for fuel, an almost limitless supply of fuel for even the leanest athlete.
Very resistant to fatigue: They are built to go and go, all day.
Recover quickly when allowed to rest.

Fast-Twitch Fibers:

Burn glycogen for fuel. This glycogen is stored within the muscles and is in relative short supply, about 2000 calories for a well-trained, well-fueled athlete.
Fatigue quickly, are NOT built to go all day.
Take a long time to recover before they can be used again.

 

[mrthingyx]

All muscle fibres contain stores of glycogen: it's how they work. Faster twitch fibres have more and slower ones have less. Faster twitch muscles do require more central nervous system drive to kick into gear (which is why fast twitch fibres have bigger innervating cells/feeds/whatever), and so they need to be pushed to do anything. However, all athletes have these: endurance athletes simply have less fast, and more slow twitch fibres. The key thing is how an athlete's genetic make-up (and training, to a small degree) expresses the proportion.

All muscles will use glycogen in the first instance because it's not that they choose to use X or Y, but because of the physics/biology involved: glycogen is easier to convert to ATP than fat, is actually stored in the muscle cells themselves, so it gets used first. It does not mean the body won't start metabolising fat, but that this process takes longer than the splitting down of glycogen. The fuel is largely irrelevant to the muscles: all they care about is ATP. Where ATP comes from is the relevant bit: glycogen (and other sources, such as phosphocreatine) provides it quickly; fat does it slowly

Endurance athletes have a higher percentage of slower twitch fibres, so they will hold less glycogen, but it is still there. So whilst those slow twitch fibres start kicking into gear, all that glycogen is being used up in the first few (tens of) minutes: the fewer fast twitch fibres an athlete has, the shorter time this will take.

The more endurance training an athlete undergoes, the more mitochondria, vasculature and other machinery required for aerobic metabolism (endurance), the more efficient they become at 'burning fat' for their exercise of choice.

So the information you provided, arknor, is correct, but is missing part of the picture. Why do you think endurance athletes carb-load prior to an event?

 

[Psycho Sonny]

The best thing you can do is sort your diet out.

Losing fat is 75% diet and 25% exercise.

Also IMO a combo of decent cardio (like running, rowing, swimming, boxing) instead of easy stuff like cycling and ellipticals is more efficient at burning calories in smaller periods of time as well as weight training is the best.

Increased muscle mass burns more energy and to make the muscles uses up energy too.

But the most important thing is your diet. No point wasting your time in doing any exercise if your going to continue eating cakes, crisps, take-aways and guzzle beer on a regular basis, your not going to see effects until you sort the diet out.