Activity Goal and BT Chest Strap Questions

Discussion in 'Apple Watch' started by opill, May 9, 2015.

  1. opill macrumors newbie

    May 9, 2015
    My first post--please be gentle : )

    Brief background--I am using the 42 MM SS AW BSB as a watch and as a replacement for my fitbit flex. So the fitness/activity aspects are important to me.

    1. I don't really feel like I understand what I am doing when I am setting my goal in the Activity App. I have set it for 500 calories. But what does that really mean? I have no reference point for that. Is that good? Will I lose weight? Every day I am hitting nearly double that. What about setting step goals? Distance goals? Flights of stairs goals? Why is setting a calorie burn goal useful? Am I over thinking this? How do you know what would be a good goal to set for yourself? Is there any credible information on this or do you just guess what the number should be?

    2. The day before my AW arrived, I bought the TICKR heart rate monitor chest strap. I used it on a run with the chest strap connected via BT to my iPhone 6 Plus not the AW. Outdoor run was selected in the Workout App on AW. On this run AW said total cals (rest + active) were 539 with 157 Avg BPM. The TICKR gave total cals at 663 with 149 Avg BPM. Today, I did Crossfit and our workout was all cardio. I used the TICKR connected via BT to the AW. I liked how I had quick access to my HR. Even though I have done similar workouts this week with just the AW--no chest strap--my total calories today seemed significantly higher (200) than when I have done similar workouts with just the AW and the Workout App set to Other. My question is---is the chest strap overkill? I keep reading these pieces online about how accurate the HR monitor is on the AW, but my feeling is I am getting more accuracy with the chest strap. Any thoughts on this? Obviously, I would rather not wear a chest strap. And the TICKR App does know my age, gender, and weight.
  2. flur macrumors 68020


    Nov 12, 2012
    In order for you to lose weight, you need to burn more calories than you're taking in. You can sort this with lots of tracking and apps and stuff, or you can do it the easy, time-tested way - by simply figuring out what you normally burn to maintain your weight according to the device you're using (the watch) and then creating a goal that increases that.

    As far as the chest strap goes, that's always going to be a more accurate way to get heart rate.
  3. H3rman macrumors 6502

    Apr 16, 2015
    1. Calories is a measure of energy. So to loose weight you need to burn more energy (calories) than you consume. If you eat 2,000 calories in a day and burn 2,000 calories you will maintain weight.

    Now 1lb of fat contains approx 3,500 calories worth of energy, so if you consume 2,000 calories a day and burn 2,500 calories a day than you will be burning 500 calories more than you are consuming. Over 7 days that adds up to 3,500 calories and you should lose about 1lb of fat.

    The thing is your absolute weight can be meaningless. If you exercise a lot you can lose 1lb fat and gain 1lb of lean mass (muscle), so you weight will remain the same, but you are getting healthier. This is why it's important to check your body fat percentage and calculate your lean mass and fat mass so you know if you are improving of not. Just taking you weight means nothing. You could be in the "healthy" BMI range but have the majority of you be fat. On the other hand I have met people where their BMI is "grossly obese" where as in reality they are only 10% body fat and extremely fit, but have lots of muscle which makes them weigh more.

    2. Chest strap will ALWAYS be more accurate than the watches built in HRM. The strap measures directly off the chest and picks up the electrical impulses your heart makes as it pumps. The watch uses light and determines your heart rate on how the light is reflected back, because as your heart pumps your arteries expand and contract, which alters how the light is reflected back. So that what it uses to pick it up.

    Problem is that when doing weight lifting and what not, as your muscles exert more force they can expand and constrict the veins around them, so while your heart is pumping hard the watch won't see it because it can't see the arteries expand and contract due to the muscles around constricting them. A chest strap doesn't have this issue. However it is not an issue you will have with cardio workouts.

    The chest strap will also detect changes quicker and more accurately than the watch. The watch is great if you don't have a chest strap, but the technology is somewhat limiting, however on the other hand it is much more convenient than wearing a chest strap all the time.

    For your planned workouts and gym sessions, stick with the chest strap if you can, the watches built in one can be used as a backup one for situations where you forget your chest strap.
  4. opill thread starter macrumors newbie

    May 9, 2015
  5. tivoboy macrumors 68040

    May 15, 2005
    calculating fat can be inaccurate especially if one is new to the process..with new clients during an actual TAPE measurement of various locations (same ones each time) will give a better more accurate indication of FAT LOSS vs. MUSCLE GAIN over medium length periods.

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