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Study: Smoking joints doesn't affect regular cannabis users' cycling ability

No difference found in negotiating obstacle course when clean or after three joints, say researchers

A new study says that smoking a joint - or three - of cannabis does not affect the ability of regular users of the drug to ride a bicycle.

Led by Dr Benno Hartung of the University Clinic in Düsseldorf, researchers had the 14 participants in the study – 12 men and two women – ride around an obstacle course.

Each undertook a number of rides on the course, the first sober, the others after smoking one, two or three joints, reports the Smell the Truth blog on the San Francisco Chronicle's SF Gate website.

For each puff of the joint, they were required to inhale for four seconds then hold their breath for a further 10 seconds.

They had points deducted for riding errors such as ignoring red traffic signals, hitting obstacles and going off course, enabling researchers to draw up a score for each run.

 The study, published in the International Journal of Legal Medicine, concluded: “Hardly any coordinative disturbances could be detected under the influence of high or very high THC concentrations.

“Only a few driving faults were observed even under the influence of very high THC concentrations … On average, there is no increase in the number of demerits after the cannabis consumption.”

However, the study’s authors underlined that participants were regular cannabis users and that the research suggested habitual users have a different response to THC than those who do not use the drug.

 “A defined THC concentration that leads to an inability to ride a bicycle cannot be presented,” they said.

“The test subjects showed only slight distinctive features that can be documented using a medical test routinely run for persons under suspicion of driving under the influence of alcohol or drugs.”

Last May we reported on two other studies led by Dr Hartung that assessed the ability of people to ride a bike while under impaired – one when drunk, the other while hungover.

> Study: Men safer in the saddle than women when extremely drunk

> Riding the morning after: How safe is hungover cycling?

 

Simon joined road.cc as news editor in 2009 and is now the site’s community editor, acting as a link between the team producing the content and our readers. A law and languages graduate, published translator and former retail analyst, he has reported on issues as diverse as cycling-related court cases, anti-doping investigations, the latest developments in the bike industry and the sport’s biggest races. Now back in London full-time after 15 years living in Oxford and Cambridge, he loves cycling along the Thames but misses having his former riding buddy, Elodie the miniature schnauzer, in the basket in front of him.

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14 comments

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Mungecrundle | 6 years ago
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Acid test. Would you be OK if you saw the surgeon who was about to operate on you sharing a spliff with the aneasthetist in the scrub room as you are wheeled into theatre?

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hawkinspeter replied to Mungecrundle | 6 years ago
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Mungecrundle wrote:

Acid test. Would you be OK if you saw the surgeon who was about to operate on you sharing a spliff with the aneasthetist in the scrub room as you are wheeled into theatre?

Depends on the procedure. If it was an everyday operation like an ingrown toenail, then I wouldn't necessarily be worried and I'd be more concerned if I saw them chugging a pint of espresso and had shaking hands. The worst would be a surgeon that looked nervous.

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Yorkshire wallet | 6 years ago
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If you drink/smoke weed/lick toads and then cycle you are a twat. Only smoked weed and drove  once and as previous post says, I could tell I wasn't sharp at all (blunted!) and never did it again.

Cycling is safest when you're on the ball, not impaired. No use crying about driving standards if you can't live by the ones you set for other people.

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hawkinspeter replied to Yorkshire wallet | 6 years ago
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Yorkshire wallet wrote:

If you drink/smoke weed/lick toads and then cycle you are a twat. Only smoked weed and drove  once and as previous post says, I could tell I wasn't sharp at all (blunted!) and never did it again.

Cycling is safest when you're on the ball, not impaired. No use crying about driving standards if you can't live by the ones you set for other people.

False equivalence?

Being impaired whilst driving puts other people at risk, whereas being impaired whilst cycling typically puts yourself at risk (obviously there are edge cases where a cyclist kills babies or somesuch).

I've certainly cycled under the influence and to be honest I tend to take more risks when I'm sober and have definitely performed more risky maneouvres. However, I did scrape my hand on a wall once when I was very drunk and unicycling home.

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OldRidgeback | 6 years ago
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Hmm, research on drivers shows that cannabis use slows reaction times and also affects the ability to judge distances correctly. 

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jocksyboy | 8 years ago
1 like

Not sure what the point of the study was. It seems a little facile and simplistic. Being in charge of a bicycle whilst under the influence whether stoned or drunk can be exhilarating or scary. However if coordination is affected usually only one person suffers. You. A car driver under the influence is potentially a lethal weapon.

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mike the bike | 8 years ago
2 likes

Don't forget some of the bravest, most effective and most decorated soldiers in Vietnam were as high as a kite most of the time.  A little grass didn't stop them running towards the excitement.

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OldRidgeback replied to mike the bike | 6 years ago
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mike the bike wrote:

Don't forget some of the bravest, most effective and most decorated soldiers in Vietnam were as high as a kite most of the time.  A little grass didn't stop them running towards the excitement.

In WWII Russian and German tank crews and infrantry were often drunk.

In the Royal Navy the daily rum ration continued until after WWII.

There's a reason that people in the army and navy were deliberately given alcohol.

On the other hand, the only pilots routinely given alcohol before combat were Japanese kamikaze pilots.

Can you see where I'm going with this or do you want me to spell it out?

 

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Rupert | 8 years ago
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Surely many who think it's ok to smoke weed or don't smoke weed yet will be wondering does it make you go faster ?

Is this a banned substance by the UCI ?

Probably best keeping to the lemon drizzle cake addiction.

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pakennedy | 8 years ago
5 likes

Bicycles did show a marked increase in tendency to stop suddenly at cake shops though, although this was difficult to quantify fully due to the already high levels of cake required by cyclists in general.

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charliemac74 | 8 years ago
1 like

Timed runs on an off-road downhill course may well produce different results...

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HalfWheeler replied to charliemac74 | 8 years ago
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charliemac74 wrote:

Timed runs on an off-road downhill course may well produce different results...

I used to work for a famous mtb manufacturer in the west coast of Canada many years ago. A lot of the tech's were utter stoners who liked nothing better to ride up the North Shore mountains behind Vancouver, get absolutely caned on prime BC skunk and then descend down the 3000ft mountain back home.

Not for the feint hearted. Or the sensible...

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HalfWheeler | 8 years ago
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My own experience is that you sober up pretty quick once you start cycling. Within 5 minutes in fact. Maybe it's got something to do with your circulation/CV system increasing due to effort...

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congokid | 8 years ago
4 likes

Problem is it will inevitably be leapt on by motoring organisations. Do we really need more drugged up motorists on the roads?

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