[{"data":1,"prerenderedAt":297},["ShallowReactive",2],{"content:\u002Fen\u002Fblog\u002Fenergy-consumption-during-exercise":3},{"id":4,"title":5,"alternate":6,"blogIndex":9,"body":10,"canonical":9,"description":282,"excludeFromBlogIndex":283,"extension":284,"heroBadges":9,"heroBody":282,"heroCta":9,"heroImage":285,"heroImageAlt":5,"heroImageObjectPosition":9,"heroImagePresentation":9,"heroSubtitle":9,"heroTitle":5,"heroTitleClass":9,"images":286,"language":287,"layoutIntent":288,"meta":289,"navigation":291,"noindex":283,"ogImage":9,"path":292,"publishedAt":9,"readingTime":9,"sections":9,"seo":293,"stem":294,"tag":295,"topics":9,"webflowCollection":9,"webflowItemId":9,"webflowSource":9,"__hash__":296},"pages\u002Fen\u002Fblog\u002Fenergy-consumption-during-exercise.md","Energy Consumption During Exercise",{"en":7,"nb-NO":8},"https:\u002F\u002Fwww.myworkout.com\u002Fen\u002Fblog\u002Fenergy-consumption-during-exercise","https:\u002F\u002Fwww.myworkout.com\u002Fno",null,{"type":11,"value":12,"toc":273},"minimark",[13,20,28,32,43,53,63,91,108,111,124,154,166,176,183,200,207,230,240,252,255,262],[14,15,16],"ul",{},[17,18,19],"li",{},"By Jan Helgerud, Professor of Medicine",[21,22,24],"h2",{"id":23},"oxygen-uptake-energy-conversion",[25,26,27],"strong",{},"Oxygen Uptake = Energy Conversion",[29,30,31],"p",{},"Understanding the mechanisms behind energy conversion can be complex, but here’s a clear explanation of how the body turns food into fuel.",[29,33,34,35,42],{},"Oxygen uptake — a key measure of fitness — is measured in liters per minute (L\u002Fmin). For every liter of oxygen your body consumes, it produces about ",[25,36,37,38,41],{},"5 kilocalories (kcal) ",[25,39,40],{},"of energy. In other words, when we measure your oxygen uptake, we’re actually measuring your"," energy metabolism",".",[29,44,45,46,49,50],{},"Once we know your ",[25,47,48],{},"maximum oxygen uptake",", we know the size of your body’s “engine.” But a large engine alone isn’t everything — if you're “driving a heavy truck,” it takes a lot of energy just to move your own body. That’s why efficiency matters too. ",[25,51,52],{},"Your Engine Needs Fuel",[29,54,55,56,42],{},"The food you eat provides the fuel your body needs to function. The two primary sources of fuel are ",[25,57,58,59,62],{},"carbohydrates ",[25,60,61],{},"(sugars) and"," fats",[14,64,65],{},[17,66,67,68,71,72,74,75,78,79,82,83,86,87,90],{},"**1 gram of fat ",[25,69,70],{},"provides"," 8 kcal  **- **1 gram of carbohydrate ",[25,73,70],{}," 4 kcal  **However, there's a catch: each gram of carbohydrate binds to ",[25,76,77],{},"3 grams of water",", which means you carry ",[25,80,81],{},"4 grams of weight"," for every gram of carbohydrate energy stored. That translates to just ",[25,84,85],{},"1 kcal per gram of body weight",". When carbohydrates are converted to fat in the body, the energy density increases — and the ",[25,88,89],{},"weight"," decreases by a factor of 8.",[92,93,95,96,99,100,103,104,107],"h3",{"id":94},"carbohydrates-are-limited-but-essential-because-carbohydrate-storage-is-heavy-the-body-keeps-its-stores-limited-even-when-fully-topped-up-you-only-carry-around-1-to-15-kg-of-carbohydrates-equal-to-40006000-kcal-enough-for-about-90-minutes-of-high-intensity-work-after-that-you-hit-the-wall-unless-you-refuel-or-significantly-reduce-your-intensity","**Carbohydrates Are Limited — But Essential **Because carbohydrate storage is \"heavy,\" the body keeps its stores limited. Even when fully topped up, you only carry around ",[25,97,98],{},"1 to 1.5 kg of carbohydrates",", equal to ",[25,101,102],{},"4,000–6,000 kcal"," — enough for about ",[25,105,106],{},"90 minutes of high-intensity work",". After that, you \"hit the wall\" unless you refuel or significantly reduce your intensity.",[29,109,110],{},"That said, without carbs, you couldn’t sustain high-intensity work at all. You’d be grateful for their limited but powerful presence.",[112,113,115,116,119,120,123],"h4",{"id":114},"carbs-vs-fat-whats-burning-your-body-typically-burns-a-mix-of-carbohydrates-and-fat-depending-on-intensity-and-duration","**Carbs vs. Fat: What’s Burning? **Your body typically burns a ",[25,117,118],{},"mix of carbohydrates and fat",", depending on ",[25,121,122],{},"intensity and duration",":",[14,125,126,133,139],{},[17,127,128,129,132],{},"At rest or low intensity, your body primarily uses ",[25,130,131],{},"fat"," .",[17,134,135,136,132],{},"As intensity increases (up to ~80–90% of max oxygen uptake), it shifts more toward ",[25,137,138],{},"carbohydrates",[17,140,141,142,153],{},"At ",[25,143,144,145,148,149,152],{},"high intensity ",[25,146,147],{},", only"," carbohydrates ",[25,150,151],{},"are used — because they release energy"," 2–3 times faster"," than fat.",[112,155,157,158,165],{"id":156},"interval-training-vs-long-runs-high-intensity-interval-training-relies-almost-entirely-on-carbohydrates-a-long-slow-distance-run-at-around-50-of-your-max-capacity-allows-you-to-burn-both-carbs-and-fat-and-continue-for-hours","**Interval Training vs. Long Runs **High-intensity ",[25,159,160,161,164],{},"interval training ",[25,162,163],{},"relies almost entirely on carbohydrates. A long, slow-distance run at around"," 50% of your max capacity"," allows you to burn both carbs and fat — and continue for hours.",[29,167,168,169,172,173],{},"Interestingly, ",[25,170,171],{},"fat burning peaks at 40–60% of maximum oxygen uptake",", but even then, you're still burning carbohydrates at the same time. It’s never just one or the other. ",[25,174,175],{},"How Duration Affects Fuel Use",[29,177,178,179,182],{},"The ",[25,180,181],{},"longer"," you exercise, the more the body shifts toward fat as fuel. For example:",[14,184,185],{},[17,186,187,188,191,192,195,196,199],{},"During moderate work at **60% max oxygen uptake ",[25,189,190],{},"for"," 90 minutes ",[25,193,194],{},", the body may start by burning"," 60% carbs \u002F 40% fat  **- As glycogen stores dwindle, this may shift to ",[25,197,198],{},"40% carbs \u002F 60% fat"," by the end",[29,201,202,203,206],{},"Still, ",[25,204,205],{},"duration alone"," doesn’t give you the same training effect as intensity.",[112,208,210,211,42],{"id":209},"moderate-training-isnt-enough-prolonged-moderate-intensity-training-is-not-our-recommended-approach-for-improving-fitness-for-example-youll-burn-the-same-amount-of-energy-in-a-30-minute-4x4-interval-session-as-you-would-in-50-minutes-of-moderate-training-even-though-the-interval-workout-is-40-shorter","**Moderate Training Isn’t Enough **Prolonged moderate-intensity training is ",[25,212,213,214,217,218,221,222,225,226,229],{},"not ",[25,215,216],{},"our recommended approach for improving fitness. For example, you’ll burn the"," same amount of energy ",[25,219,220],{},"in a"," 30-minute 4x4 interval session ",[25,223,224],{},"as you would in"," 50 minutes ",[25,227,228],{},"of moderate training — even though the interval workout is"," 40% shorter",[29,231,232,233,235,236,239],{},"When it comes to building ",[25,234,48],{},", ",[25,237,238],{},"intensity"," is key. Duration simply can’t replace it.",[241,242,244,245,42],"h5",{"id":243},"heres-the-paradox-new-research-shows-that-the-single-most-important-factor-for-improving-fat-metabolism-is-maximum-oxygen-uptake","**Here’s the Paradox **New research shows that the ",[25,246,247,248,251],{},"single most important factor for improving fat metabolism ",[25,249,250],{},"is..."," maximum oxygen uptake",[29,253,254],{},"And the best way to increase that?",[29,256,257,258,261],{},"High-intensity interval training — which relies ",[25,259,260],{},"entirely"," on carbohydrate metabolism.",[29,263,264,265,268,269,272],{},"The paradox is this: while interval training burns mostly carbs in the moment, it significantly improves your ",[25,266,267],{},"aerobic capacity",". As a result, you become a far better ",[25,270,271],{},"fat-burner"," in all other activities.",{"title":274,"searchDepth":275,"depth":275,"links":276},"",2,[277],{"id":23,"depth":275,"text":27,"children":278},[279],{"id":94,"depth":280,"text":281},3,"**Carbohydrates Are Limited — But Essential **Because carbohydrate storage is \"heavy,\" the body keeps its stores limited. Even when fully topped up, you only carry around 1 to 1.5 kg of carbohydrates, equal to 4,000–6,000 kcal — enough for about 90 minutes of high-intensity work. After that, you \"hit the wall\" unless you refuel or significantly reduce your intensity.","The more you move, the more energy your body uses. But how exactly does the body burn energy — and what types of exercise lead to the highest energy expenditure?",false,"md","webflow-6847de9cbed1fcc64a034b84-screenshot-202025-06-10-20at-2009-28-20-65d0f563c285",[285],"en","Imported from Webflow CMS as a public content page.",{"seoStatus":290},"migrated",true,"\u002Fen\u002Fblog\u002Fenergy-consumption-during-exercise",{"title":5,"description":282},"en\u002Fblog\u002Fenergy-consumption-during-exercise","good-to-know","FpNdxesJkxljNTrC4RJQNVj_n3ny1ebKy6xs5JHwvww",1783582677873]