Saturday, July 26, 2014

Too Much Sitting Negates The Benefits Of Your Exercise

Picture by Carsten Knoch from Flickr
Since my earlier post on Runners Run A Lot, Also Sit A Lot, I've received quite a few questions on how much does sitting affect us. So here's a follow up post on that article.

Well, to answer your queries, according to research, each hour of sitting negates 8 % of your gain from an hour's worth of running. So if you ran an hour this morning and then sit for 10 hours after that during the day, you lose about 80% of the health benefit you gained from your morning run.

That's rather upsetting isn't it? I've never thought I had to subtract (any health benefit) from my exercise before. Fortunately for me, I don't sit much during the day when I'm treating my patients. I sit most when I'm reading doing research and writing articles for this blog.

Now for the not so good news. If you do an hour's worth of moderate intensity exercise (running is considered vigorous exercise), you lose about 16 % of your workout gains from each hour of sitting.

The above mentioned data were the same for both men and women.

Researchers obtained the results through analysis of objective fitness and exercise data obtained through the National Education and Nutrition Survey (NHANES). This is an annual survey conducted to assess the country's exercise and nutrition habits.

So for office workers and those who work from home and are mostly sitting, you should be walking up stairs rather than using the lifts, stand while talking on your phone, sitting on a gym ball, using a standing desk, walking out during your lunch and use a pedometer to log your dally step count.

As Little Eva (and later Kylie Minogue) sang, "So come on come on, do the loco-motion with me." 


Kulinski JP, Khera A, Ayers CR et al (2014). Association Between Cardiorespiratory Fitness And Acclerometer-derived Physical Activity And Sedentary Time in General Population. Mayo Clinic Proceedings. DOI: 

Surely I can sit now after all that walking ....
Picture by Julio Velasco from Flickr.

Friday, July 18, 2014

Organic Food Has Higher Antioxidants

Picture by Basak Ekinci from Flickr
My wife is a firm believer in eating well. Even before my accident she's been buying organic food for the family. After my accident, eating organic in our household went up a few notches. I've been having green juices, organic cocoa and lots more. If you've been reading some of my older posts, you'd know I basically ate anything and everything, especially junk food and drinking lots of Coke too. I figured that since I exercise (and trained pretty hard before) I could eat anything I wanted.

Guess what, turns out my wife was right all along. According to a paper published in the British Journal of Nutrition (which reviewed 343 studies), you get 20-40 % more antioxidants if you switch from normal conventionally grown (read plenty of pesticides) to organic food. Antioxidants are thought to prevent or delay some types of cell damage and can therefore improve your health and slow the aging process.

Conventionally grown food were 3 to 4 times more likely to have pesticide residues and twice as likely to contain cadmium (a toxic heavy metal contaminant). This study differs differs from previous studies which concluded there were no significant differences in antioxidant content between conventional and organic produce.

This study's authors wrote that their finding is more reliable since more studies were analysed using more sophisticated means of analysis.

One suggested reason by the authors that organic food is higher in antioxidants is that plants produce chemicals that form antioxidants in response to environmental stress like pests, diseases and lack of soil nutrients. Since conventionally grown produce are mostly shielded from these stresses, conventionally grown produce do not produce antioxidants.

The second reason is that conventionally farming uses nitrogen with a much higher nitrogen content leading plants to produce fewer antioxidants.

Well, maybe it's time to look at what you eat.

Baranski M et al (2014). Higher Antioxidant And Lower Cadmium Concentrations And Lower Incidence Of Pesticide Residues In Organically Grown Crops: A Systematic Literature Review And Meta-Analyses. Brit J of Nutrition. FirstView Article pp 1-18. DOI: 10.1017/S000711454001366.

Some of the organic snacks my wife bought for my son

Friday, July 11, 2014

Oakley 30 Years Heritage Radarlock, Frogskins And Oakley Chainlink

What I got today
I received 3 pairs of Oakley sunglasses today. The 30 years Heritage Radarlock and Frogskins and the Oakley Chainlink. A big thank you to Joey.

Here'a a closer look at the Radarlock Path.

"30" etched on the lens
Many thanks to Joey from Oakley.

Sunday, July 6, 2014

Runners Run A Lot, Also Sit A Lot

Potatoes picture from Flickr
You're very active. You may average between 30-40 miles (48-68 km) a week while training for your half or full marathon, running an average of an hour almost daily. You also sit a lot while not exercising or running, close to 8 hours hours or more a day at times. Does this sound like you? You may be what researchers term an "active couch potato."

A group of researchers studied runners (average age of the 218 runners was 35, slightly more than two-thirds were women) who competed in the Austin half and full marathon. These runners ran almost an hour a day (making them among America's most active adults). The runners sat a lot too, ranging from 8 to 11 hours daily.

While looking at the demographics of the runners, a large number of then tend to be professionals with office type desk bound jobs. Is that you?

There were big differences between workday and non workday activities for these runners. The runners slept seven hours a night in the work days and sat about 11.4 hours. While not working, they slept eight hours and sat about 8.5 hours.

There was no connection between training time and sitting time, meaning runners who ran more did not sit more or less than those who ran less. Their results suggest that the runners' sedentary behaviours did not displace their moderate to vigorous activities (running or other exercises). The two coexist at high levels in this study.

This study did not say that the runners' sitting time was unusually high or that it led to any health outcomes although other studies have shown that sitting time is an independent predictor for diabetes, high blood pressure, heart diseases and most other lifestyle diseases (Katzmaryzk et al 2009). In other words, excessive sitting may cancel out some of the benefits of your exercise.

These runners' are " simultaneously highly sedentary and highly active." The authors suggested that these runners' may be a good group for future studies. This may give us more information on how much we have to exercise to negate the harmful effects of sitting.

After spending all that time sitting, researching, reading and then typing this article, I'd better get up and stop sitting.


Whitefield G et al (2014). Sedentary And Active: Self-reported Sitting Time Among Marathon And Half-marathon Participants. J Phys Act Health. Jan 11(1): 165-172. doi: 10.1123/jpah.2011-0410.

While I was still actively training, once I came home after a hard swim, bike or run, I'll be sitting, eating or sleeping.....

Sunday, June 29, 2014

Can Running (And Other Endurance Sports) Lead To Worse Dental Health?

Picture by Jason Lee from Flickr
While out with my son earlier today, I met a patient asking why I hadn't written recently. I told her that since Luis Suarez and his teeth attracted attention for all the wrong reasons recently at the World Cup, I'll be writing a post on teeth as well. She then asked me what does running have to do with teeth?

Well here you go Audrey, a post on how running (or endurance exercise) can affect your teeth.

A group of German researchers studied a group of triathletes and non athletes and found that the triathletes had significantly higher rates of tooth erosion. What's more, among the athletes, those who trained harder had more cavities than those who trained less.

The researchers found that 46% of the athletes consumed sports drinks while training, while 51% drank water. 74% used gels or bars during training. Both groups revealed no significant difference in cavities, but those who trained the most amongst the triathletes had the most cavities. There was also a highly significant difference in the triathlete group for tooth erosion.

Like me, you must be starting to scratch your head and wonder why. Well, due to the triathletes high carbohydrate consumption of which includes gels, bars and sports drinks during training, their mouth's pH levels are below 5.5 (and  hence acidic), leading to dental erosion and cavities. In addition, during hard training, the athletes breathe through their mouth, making the mouth dry and produces less saliva (more acidic), which normally protects the teeth.

Note that both groups had similar saliva profile at rest. Only when the athletes begin exercising then they had less saliva. Degree of acidity increased with the length of time spent exercising.

The researchers concluded that endurance training has a detrimental effect on oral health.

This view has been raised before by Needleman and colleagues who found poor dental and even overall health in many Olympic athletes at the London 2012 Olympics (Needleman et al, 2013). Prof Tim Noakes suggested that this may happen due to their high carbohydrate diet and the frequent ingestion of sports drinks.

So make sure you brush your teeth following your bike or run session, especially if you've consumed gels, bars or sports drinks during or after your run.


Needleman I, Ashley P et al (2013). Oral Health And Impact On Performance Of Athletes Participating On The London 2012 Olympic Games: A Cross-sectional Study. BJSM. 47:1054-1136.doi: 10.1136/bjsports-2013-092891.

Frese C, Frese F et al (2014). Effect Of Endurance training On Dental Erosion, Caries, And Saliva. Scan J Med Sci Sports. doi: 10.1111/sms.12266.

Always clean your teeth after you run
Picture by doc18 from Flickr

Friday, June 20, 2014

Shin Splints Most Common In New Runners

Picture by Anne Sophie from Flickr
Latest published  research indicates that shin pain is the most common complaint among new runners. Shin splints or stress fractures is also our most popular article in this blog with over 200 comments and counting.

The researchers studied 933 new runners for a year to see how many were injured, what injuries they had and how long it took before they resumed running. They were considered new runners if they haven't run more than 10 kilometres the previous year. The runners were considered injured if they had running induced pain in their legs or lower back that prevented them from training (distance, duration, pace or frequency) for at least a week.

254 runners were injured during their first year of running. 15% of this injured runners had medial tibial stress syndrome (or shin splints), 10% had knee pain, 7% injured their Achilles tendons while 5% hurt their plantar fascia or soleus (deep calf muscle).

Stress fractures were relatively rare, probably because the new runners' mileage in their first year were not high enough. 75% of the injuries happened during the runner's first 201 kilometres.

Time to heal varied widely amongst the injured runners.Those who hurt their calf resumed training after 30 to 40 days, while those with shin pain took an average of 72 days to fully recover. The worst were those who had plantar fasciitis, it took an average of 159 days to recover.

Majority of the 254 injured runners recovered fully (220) by the end of the year long study. Only 34 remained injured.

The researchers concluded that their findings emphasized the importance of the need for new runners to be mindful of shin splints as it is most common injury in their study. Even among recreational and elite runners, shin splints was the most common injury with an incidence of 13-20% (Lopes et al 2012).

Wanna run pain free? Have a read here.


Lopes AD, Hespanhol Junior LC et al (2012). What Are The Main Running-related Musculoskeletal Injuries? A Systematic Review. Sports Med 42: 891-905.

Nielsen RO et al (2014). A Prosepective Study On Time To Recovery In 254 Injured Novice Runners. PLOS One. DOI: 10.1371/journal.pone.099877.

Even Kobe has shin pain. (Picture from Flickr)

Friday, June 13, 2014

A Hard Warm Up Helps You Run Faster

Weight vest from Flickr by Dennis S Hurd
Wanna run faster in your next race? Turns out a hard warm up can help you run faster before your race.

If you've ever been to a track meet and seen the runners warm up, you'll probably see them jog/run a fair bit, do some running drills, short sprints or strides (depending on their event) and other fairly vigorous activities as part of their warm up. You'll probably see the same prior to hard track/ interval sessions of some runners if you run at your local track. Usually the shorter the race, the more intensive the warm up.

Now there's research backing this up. Researchers studied a group of runners who went through their warm up and a race simulation thereafter on 2 occasions.  Before each race simulation, the runners (as part of their warm up) did 10 mins of easy jogging, 5 mins at a brisk (but not all out pace), six 10-seconds of striding (or accelerations at their mile race pace or faster). The runners rested 10 mins and did a series of jumps, another submaximal 5 min run and then a treadmill test at peak running speed.

That's some weight vest! (Picture by Ving Henson from The Pit
The only difference was the runners wore a weighted vest while doing their 10-second striding. The runners after warming up with the weight vest had results significantly better. Their running economy was 6% better on the post striding 5 min run, peak running speed was 2.9% faster! (Running economy measures your running efficiency. You can run faster at the same effort if your running economy improves as that pace will feel easier, hence elite runners often use intervals to improve their running economy).

The researchers think that increased "leg stiffness" noted in the post striding jumps primed the legs and improved running economy in the runners, leading to faster times. I suppose an exercise scientist would say that running with the weight vest causes neuromuscular training adaptations (which means your brain is also being trained)  which makes the runners' legs stiffer so their running economy improves.

If you said "Jump", I'd say "How high?" Picture from The Pit.
A similar scenario may be felt for those of you who run intervals. You will probably notice that during your first 2-3 reps (of say a 10 x 1 km interval session) will feel more difficult than the next few reps as your body acclimatizes.

Now before you go and order that weight vest, do keep in mind that this work best for track middle and long distances and for road races up to 10 km. You should also try this in your interval training sessions and before low key races to see how it works for you before trying it prior to an important race.


Barnes KR, Hopkins WG et al (2013). Warm-up With A Weighted Vest Improves Running Performance Via Leg Stiffness And Running Economy. J Sci and Med in Sport. DOI: 10.1016/j.jsams.2013.12.005.