Intensity to MET
Exercise intensity is basically your personal "effort dial." It is both how hard it feels in the moment and how hard your body is working behind the scenes. Two people can do the same workout at different intensities because fitness, sleep, stress, heat, and even hydration change what "hard" means on any given day. The goal is not to chase suffering. The goal is to match the effort to what you are trying to accomplish - and to do it in a way you can repeat consistently.
In practical terms, intensity can be grouped into three useful buckets: easy, moderate, and hard. Easy feels comfortable and sustainable. Moderate feels purposeful and steady, like you are working but still in control. Hard feels challenging and demands focus, and you cannot hold it for long. You do not need fancy gear to get this right. You just need simple checks you can repeat across activities.
The talk test is exactly what it sounds like: can you talk while you exercise? At an easy intensity, you can speak in full sentences without gasping. At a moderate intensity, you can speak in short sentences, but you would rather not chat nonstop. At a hard intensity, you can only get out a few words at a time, and talking feels annoying or impossible.
Real-world examples: On a walk, easy is strolling and chatting. Moderate is brisk walking where you can still answer questions but you notice effort. Hard is power walking up a hill where you are mostly quiet. On a run, easy is a conversational jog. Moderate is a steady run where you can talk briefly. Hard is a fast effort where you can only say a couple words. On cycling, easy is spinning smoothly on flat roads. Moderate is a steady pace where your legs feel warm and you can speak in short bursts. Hard is pushing a big gear or climbing where you are too busy breathing to talk much.
Perceived effort is your internal rating of effort. You can use a simple 1 to 10 scale. Easy is around 2 to 4, moderate is around 5 to 6, and hard is around 7 to 9. A 10 is an all-out effort you can only hold briefly. This works for cardio and strength training because it captures more than speed or weight - it includes fatigue, stress, and sleep.
Examples: For swimming, an easy pace feels smooth and controlled (RPE 3 to 4). Moderate feels like you are working and your form needs attention (RPE 5 to 6). Hard feels like each length demands focus and you want rest at the wall (RPE 7 to 8). For strength training, easy might be a set where you could do 5 or more extra reps with good form. Moderate is a set where you could do 2 to 3 extra reps. Hard is a set where you might have only 0 to 1 reps left in the tank while still keeping form clean.
Your breathing pattern is one of the most reliable no-gear signals. Easy intensity usually means nasal breathing is possible most of the time and you recover quickly if you pause. Moderate intensity often shifts you toward mouth breathing, but it still feels rhythmic and controlled. Hard intensity brings deep, frequent breaths, and you may feel like you need to slow down to regain control.
Concrete examples: Walking easy might let you breathe through your nose comfortably. Moderate walking might switch you to mouth breathing on hills. Hard walking has you taking big breaths and wanting to stop at the top. Running easy is light breathing you barely notice. Moderate running is steady breathing you can manage. Hard running is fast breathing where you are counting steps to stay composed. Cycling hard often feels like strong leg burn plus heavy breathing, especially on climbs. Swimming hard usually forces you to time breaths carefully and you feel a strong urge to rest after each interval.
Walking: Easy is a relaxed pace you could do for a long time, like an errand walk. Moderate is brisk walking where your arms swing and you feel warm. Hard is steep hills or fast power walking where you cannot talk much. Running: Easy is a comfortable jog with light feet and a steady rhythm. Moderate is a steady run where you feel like you are training, not just moving. Hard is a fast effort like a short tempo push or intervals where you need recovery between bouts.
Cycling: Easy is smooth spinning on flat ground, minimal strain. Moderate is a steady effort where you feel pressure on the pedals but you can keep it going. Hard is climbing or pushing speed where your breathing is loud and legs fatigue quickly. Swimming: Easy is relaxed laps with focus on technique. Moderate is steady laps where you keep form but feel a clear workload. Hard is intervals where you need rest at the wall and your technique tries to fall apart. Strength training: Easy is practice sets or lighter weights where you end feeling fresh. Moderate is working sets that feel solid and leave you challenged but not crushed. Hard is heavy sets near your limit or higher-rep sets that produce strong effort while you still maintain good form.
Heart rate can be useful, but you do not need to obsess over numbers. Think of it as another clue, like breathing and talk ability. When intensity rises, heart rate rises, but it can also rise more than usual in heat, after poor sleep, when dehydrated, or when you are stressed. That is why it is best used as a confirmation, not the only driver.
Practical use: if an effort feels easy but your heart is racing, slow down and check heat, hydration, and fatigue. If an effort feels hard but your pace is low, you might be tired or coming down with something. On some days, your body asks for an easier gear. Listening to that is part of training, not a failure.
For general fitness, mix mostly easy and moderate work with small doses of hard efforts. For endurance, keep most sessions easy to moderate so you can accumulate time without burning out, and add one harder session if you recover well. For strength, focus on moderate to hard sets with excellent form and enough rest, and keep cardio mostly easy so it does not steal recovery. For fat loss, consistency matters most: choose intensities you can repeat, often easy to moderate with occasional hard bursts if you enjoy them. For stress relief, prioritize easy movement that calms breathing and leaves you feeling better afterward.
Time matters too. If you have 20 minutes, a moderate session or short hard intervals with a long warmup can work, but only if you are not fried. If you have 60 minutes, easy to moderate is often the sweet spot. Recovery status should be the boss: if sleep was bad, muscles feel heavy, or motivation is low, choose easy intensity and treat it as a win. If you feel springy and well-rested, that is the day to add moderate or hard work.
Starting too hard is the classic error. People sprint the first five minutes, then crawl, and the whole workout becomes a suffer-fest. Fix it by starting easier than you think for the first 10 minutes, then gradually building. Another mistake is ignoring fatigue signals and trying to force a planned intensity when your body is clearly not ready. Fix it by adjusting the session: keep the same time but lower the effort, or keep the intensity but reduce the duration.
Confusing soreness with progress is also common. Soreness can happen when you do something new, but constant soreness often means poor recovery or too much intensity. Fix it by spacing hard days, improving sleep, eating enough, and keeping easy days truly easy. A good rule is that you should finish most workouts feeling like you could have done a little more, not like you need to lie on the floor.
In heat, intensity feels harder faster, and dehydration sneaks up. Slow down, take breaks, choose shade, and use the talk test aggressively - if you cannot speak, you are probably going too hard for the conditions. If you feel dizzy, chilled, or unusually weak, stop and cool down. When you are sick, especially with fever, chest symptoms, or body aches, skip hard workouts. Even mild illness is a good reason to keep activity easy and short.
After a break, the biggest risk is doing "what you used to do." Start at an easy intensity for the first week or two, then add moderate work gradually. Keep hard work minimal until your joints, tendons, and lungs feel reacquainted. Progress feels boring at first, but it prevents setbacks and makes consistency possible.
Monday: Easy walk or easy cycle for 30 to 45 minutes, comfortable talking pace.
Tuesday: Strength training at moderate effort, leaving 2 to 3 reps in reserve on most sets.
Wednesday: Easy swim or easy jog, relaxed breathing and smooth technique.
Thursday: Harder session such as short run intervals or hill repeats, with plenty of recovery between efforts.
Friday: Easy movement for stress relief, like a light walk plus gentle mobility.
Saturday: Longer moderate endurance session like a steady ride, steady run, or continuous swim where you can speak in short sentences.
Sunday: Rest or very easy recovery activity, keeping effort low and focusing on feeling better afterward.