Energy cost and oxygen requirement

[Lawrence]

I've wondered about this for a long time but haven't seen it addressed anywhere. It concerns what I think of as the energy cost/oxygen usage ratio. Apologies in advance for the imprecision.

Compared with other activities:

1. is swimming at a leisurely pace a low, medium or high energy cost activity; and

2. whatever the answer to 1, does the fact that oxygen supply in swimming is constrained by the requirements of technique (you can't breathe in whenever you feel like it) mean swimming is, relative to other activities, effectively pushed up the scale towards 'higher energy cost'?

My guess on 1 is that swimming at a relaxed pace doesn't use many calories, and not appreciably more than walking, running or cycling. Perhaps it uses less, albeit we notice the effort more because our much stronger legs aren't doing most of the work.

But even if I'm right about 1, how about 2? As a rough guide, I would guess that doing something which requires half the energy but with access to only half the oxygen makes it feel about as hard as doing something needing twice the energy where there is twice as much air to breathe.

Behind all this is a desire to know how easy swimming could feel.

Anyone else wondered about this?

[cynthiam]

Interesting questions.

I agree with you regarding 1, though I suspect the cost varies with the swimmer's technique even at a leisurely pace. The perception of cost likely varies with the technique and how relaxed the swimmer feels.

As for 2, I think relaxation and technique help determine where swimming ranks on your scale. We've all seen struggling swimmers, and their energy costs seem much higher than someone with more polished technique.

And if the pace is pushed, relaxation & technique (including the type of kick) become even more important IMO.

When I do land-based exercise, my breathing technique figures into my perception of how hard I'm working. Even though I have access to air any time I want it, tension (or timing) can impede my breath and make me feel like I'm working harder. So I don't think there's exactly a 1:1 relationship between the amount of air available and how difficult a particular form of exercise feels.

There's also a mystery to me about how hard I'm actually working in the water. Sometimes I'll finish a length out of breath or with a high-ish heart rate, yet I didn't feel I was working that hard during it.

I do think about how easy swimming could feel -- more ease is what I aim for. During every pool session I do at least a few lengths focusing on ease. I get glimpses of ease and flow, where it feels like I could go on for a long time. I'm doing this at a fairly leisurely pace, though I sometimes finish a length sooner than a harder-working swimmer next to me who appears to be going faster than I am.

[aquarius]

Originally Posted by Lawrence

But even if I'm right about 1, how about 2? As a rough guide, I would guess that doing something which requires half the energy but with access to only half the oxygen makes it feel about as hard as doing something needing twice the energy where there is twice as much air to breathe.

Behind all this is a desire to know how easy swimming could feel.

Anyone else wondered about this?

Wouldn't comparing your freestyle to your backstroke give you a good idea of what the breathing constraint costs in terms of ease?

[Ken B]

Lawrence I marvel at the ease of our TI swimming every day. I routinely swim 1000m approx, 1500 sometimes now I've improved my hip drive. I choose to swim at high tide in salt water, there is always current, sometimes the water is rough and dirty, sometimes glassy calm and clear. I swim for ease and pleasure but of course I hope to get faster and more competent in different circumstances by practice and mindful swimming. To the point; I climb out at the end of a swim and I'm not breathing hard and my heart is not racing. Sometimes I wonder if it could even be called exercise. I am now a bilateral breather and I'm amazed to find that I get all the air I want. Even if I get a face full of water there is no rush to get the next breath. Compared with the oxygen requirements of running and cycling it is amazing. More speed and comfort will come from improved technique so I don't anticipate much more oxygen being required for that. Fright however can up our heart rate and breathing. Sharks, rays and seals for instance can startle.
So, nothing scientific, just personal observations, but not out of place with Terry's philosophising I think.

[aksenov]

Let’s look at MET equivalents of vigorous (>6.0 METs) physical activities (MET is metabolic equivalent)
Jogging at 5 mph = 8.0
Jogging at 6 mph = 10.0
Running at 7 mph = 11.5
Shoveling, digging ditches = 8.5
Basketball game = 8.0
Skiing cross country — slow (2.5 mph = 7.0; fast (5.0–7.9 mph) = 9.0
Soccer — casual = 7.0; competitive = 10.0
Tennis singles = 8.0
Swimming — moderate/hard = 8–11
Note: MET values can vary substantially from person to person during swimming as a result of different strokes and skill levels.
Source: Table 2 in “Physical Activity and Public Health. Updated Recommendation for Adults From the American College of Sports Medicine and the American Heart Association”, 2007

[CoachSuzanne]

Originally Posted by Lawrence

I've wondered about this for a long time but haven't seen it addressed anywhere. It concerns what I think of as the energy cost/oxygen usage ratio. Apologies in advance for the imprecision.

Compared with other activities:

1. is swimming at a leisurely pace a low, medium or high energy cost activity; and

2. whatever the answer to 1, does the fact that oxygen supply in swimming is constrained by the requirements of technique (you can't breathe in whenever you feel like it) mean swimming is, relative to other activities, effectively pushed up the scale towards 'higher energy cost'?

My guess on 1 is that swimming at a relaxed pace doesn't use many calories, and not appreciably more than walking, running or cycling. Perhaps it uses less, albeit we notice the effort more because our much stronger legs aren't doing most of the work.

But even if I'm right about 1, how about 2? As a rough guide, I would guess that doing something which requires half the energy but with access to only half the oxygen makes it feel about as hard as doing something needing twice the energy where there is twice as much air to breathe.

Behind all this is a desire to know how easy swimming could feel.

Anyone else wondered about this?

Yes, this has been thought about before extensively.

Swimming at any speed has a high energy cost compared to land based activities when assessed by power in vs. power out. Note that power in is directly calculated from oxygen cost.

example in the abstract here:
http://www.ncbi.nlm.nih.gov/pubmed/2381310

Gross efficiency of competitive swimmers in this study ranged from 5 to 9.5% with the highest values being in male competitive swimmers (like Phelps). For most of us recreational or age - group competitive level swimmers, our efficiency is more likely in the 3-5% range.

Walking, Running & Cycling, on the other hand, have a gross efficiency of around 22-27% across the board (ie... my mom's cycling efficiency vs. lance armstrong's efficiency at either end of the spectrum).

Swimming's higher energy cost is not limited by oxygen availability, rather by technique and drag presented by the medium, water. Poor swimming technique, particularly the breathing stroke, will magnify technique problems, increasing drag and making efficiency plummet.

I would argue that you can breath whenever you want, albiet with the tradeoff of slightly increased drag/decreased propulsion depending on your technique. The better your breathing technique is, the less you'll be slowed. But the slowing is not a result of decreased oxygen availabilty, rather increased drag...which perpetuates the problem of increased oxygen demand & increased ventilatory requirements, requiring more frequent breathing.

[CoachSuzanne]

Originally Posted by aksenov

Let’s look at MET equivalents of vigorous (>6.0 METs) physical activities (MET is metabolic equivalent)
Jogging at 5 mph = 8.0
Jogging at 6 mph = 10.0
Running at 7 mph = 11.5
Shoveling, digging ditches = 8.5
Basketball game = 8.0
Skiing cross country — slow (2.5 mph = 7.0; fast (5.0–7.9 mph) = 9.0
Soccer — casual = 7.0; competitive = 10.0
Tennis singles = 8.0
Swimming — moderate/hard = 8–11
Note: MET values can vary substantially from person to person during swimming as a result of different strokes and skill levels.
Source: Table 2 in “Physical Activity and Public Health. Updated Recommendation for Adults From the American College of Sports Medicine and the American Heart Association”, 2007

Great comparisons. note that MET looks only at energy expendature..so while jogging at 5mph and moderate/hard swimming both consume 8 or so METs, the OUTPUT of said activities varies drastically (ie you'll travel much further/faster jogging than swimming).

Looked at a different way, the fastest human swimming speeds are around 5mph, and can be sustained for less than a minute...whereas I can jog 5mph for quite some time.

Same input in water vs. land(METS) = much lower output for water sports = much less efficient for water
Same output (mph) = much higher input for water sports vs. land = much less efficient for water

[haschu33]

I read in more than one article which I think came from German University studies that 80% of the energy spent while swimming contributes to maintaining the body temperature. That would mean that swimming is never as costless as walking, no matter the pace.

[aksenov]

It may be a complete surprise to many, but freestyle was shown to be the most economic among the competitive swimming strokes, followed by the backstroke, the butterfly and the breaststroke.
http://www.ncbi.nlm.nih.gov/pubmed/16612740

And most probably Total Immersion subtype of freestyle (if performed perfectly) is much more economic than “average” freestyle.

[Richardsk]

Originally Posted by aksenov

It may be a complete surprise to many, but freestyle was shown to be the most economic among the competitive swimming strokes, followed by the backstroke, the butterfly and the breaststroke.
http://www.ncbi.nlm.nih.gov/pubmed/16612740

And most probably Total Immersion subtype of freestyle (if performed perfectly) is much more economic than “average” freestyle.

This is all probably true but even so I think it varies from individual to individual. For me breaststroke is without doubt the easiest to swim, although probably slower than freestyle for any distance above 50m (last year my best 100m breast time was faster than my best 100m free time, but that's probably an aberration). My butterfly, such as it is, is definitely much more strenuous than any of my other strokes.