Friday, 8 December 2017

Cycling's Recommended Minimum Daily Allowance. Do you ride your bike enough to maintain good health ?

Do you ride your bike enough to maintain good health ? I suspect that many people actually do not. A surprising amount of cycling is required if that's the main thing you do for exercise

Many sources suggest that half an hour a day of exercise is around the minimum to maintain good health.

My racing bike. A left-over from the 1980s, steel frame and
non-indexed gearing. Not the most comfy choice for me for
long rides, ideal for a quick spin around town & countryside
Because I work from home, I don't have a commute forced upon me, as was the case in the past. That means I don't automatically get a daily dose of cycling by going to work and back. Our deliveries are all made at least partially by bike, but while that means I'm riding a relatively heavily loaded cargo bike, the short round-trip distance of about 3 km doesn't take long enough. For that reason, I go out for a "commute" on at least some mornings even though I don't have to.

This morning I rode a little over 16 km, going through the town, stopping for traffic lights, heading out into the countryside against a stiff headwind and returning home again with a tailwind which of course can never add as much as the headwind already took away. It took me 31 minutes to cover the distance. I'm not about to set any records at that speed. That's not the point. This is moderate exercise, taking it fairly easy, expending enough effort to get slightly out of breath sometimes, enough to raise a bit of a sweat but certainly not enough to make my heart pound as if is going to pop out of my chest.

Recommended Minimum Daily Allowance - 15 km
At a moderate rate of exertion, 30 minutes of cycling at a rate conducive to maintaining health equates to covering about 15 km at an average speed of about 30 km/h. 15 km per day equates to about 100 km per week or about 5500 km a year. i.e. it takes about 5500 km of cycling each year to do enough exercise to maintain health.

Another day, with company, I rode another trusted old friend
on which I've ridden many thousands of kilometres over the
last 20 years.
If you ride a round-trip commute of around 21 km (13 miles) each day five days a week then that's just about perfect and will add up to about the annual target figure. If your commute is shorter, take a detour sometimes. People like me who don't have a regular commute to account for 5500 km (3300 miles) each year probably ought to get out on their bikes more often, which is what I do these days.

An inexpensive bike computer helps keep track of the total. It's December and we're heading into winter, but that's no reason to stop: Cycling in winter is particularly rewarding.

How this relates to other means of transport
If cycling is to benefit us as exercise as well as a form of transport it should be our first choice for at the first 5000 km that we travel each year. Until we've covered that distance we can consider the cost of the "fuel" used to cycle to be zero as the alternative would be to burn away the same amount of energy by wasting it at a gym or in some other sporting activity.

Motor vehicle enthusiasts occasionally make an absurd claim that the environmental cost of providing food to humans riding bicycles makes us so much less efficient than modern motor vehicles that we'd be better off driving a car than riding a bike. It's nonsense of course. Bicycles are the most efficient vehicles on the planet by some margin. This goes double for the first 5000 km because expending that energy through our bodies isn't optional. We don't need to eat extra to be able to ride those kilometres, we merely need to eat what is required to maintain a healthy weight while also taking a healthy amount of exercise.

I sometimes write about health and cycling, but I am not a doctor. In particular, I am not your doctor and I certainly cannot offer health advice to you personally. If you need health advice or you're thinking about changing your exercise habits please see a professional.


Andy said...

My regular work commutes get me right around 5000 km a year. Then I get the same again from cycling for shopping, bars, restaurants, visiting friends, and occasional purely recreational rides.

My current work commute is 9.3 miles (just under 15 km) each way. If I ever change jobs and move, my goal will be a 5-6 mile (8-10 km) commute each way. I can then still ride more if I choose to, but be under half an hour from home.

screencleaner said...

16 km. thats about 10 miles. so about 20 miles an hour.
I count myself as reasonably fit, but I would be blowing out of my ar$e to maintain that for 30 minutes. especially having to contend with traffic, traffic lights, hills etc. perhaps you are just too fit.

Andy said...

@screencleaner, yes, I typically take 40-45 minutes to do my 15 km commute. I can ride at 20 MPH, but no way can I average that.

David Hembrow said...

@Andy, screencleaner: My fittest days are some time behind me. I'm a somewhat overweight over 50 year old and these days I'm not close to being competitive even as a "senior". There's really nothing exceptional about riding at 30 km/h. I am sure you could both increase your average speeds to that level if you tried in the right location and you want to do so. It just takes more cycling.

Nine years ago I had a 30 km each way commute by bike. It which usually took around 52 minutes to cover that distance (~ 34 km/h). On re-reading that blog post I'm reminded that when I was in my twenties and lived in the UK my average commuting speed was much lower. At that time I'd average only about 22 km/h, my speed being impacted by poor roads and traffic lights.

At least every other day I try to go for a reasonably spirited ride to maintain my fitness. This morning I rode 15.5 km in 27.5 minutes (an average of 33.8 km/h, 21 mph) which was pleasingly close to my old commuting speed. I took a not especially quick route, riding off our driveway, along residential streets, out of our suburb, through the countryside a bit at 40 km/h, through a village with a 30 km/h speed limit and cobbled surface, before returning home again to stop on the same driveway and stop the timer on the computer. The route includes several sharpish corners which required slowing a lot as well as a steep bridge over which my speed dropped to just 22 km/h as I went over the top. I used to go over that same bridge with a beetroot coloured face at 30 km/h, but I don't like to push my heart to that extent any more.

My slowest bike is an upright town bike with three speed hub and baskets front and back with "women's" dropped frame (pretty much identical to this). I reset the computer three weeks ago and since then have used it for the usual combination of short trips such as shopping, taking the dog by trailer to walk in a forest and going to nightschool (Dutch). The computer on this shows an average speed of 17.6 km/h for the last three weeks. I generally ride that bike at 25-27 km/h. 27 was my rolling speed last night returning from nightschool with the dynamo on - it was below freezing which gives a choice of pedal hard or get cold.