Category Archives: Cardiovascular

Anti-Inflammatories and Anti-Oxidants in Licorice: Is Licorice good before a workout?

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This article started in response to a question: “what is the best supplement to take before a workout.”  Licorice seems as good a choice as several other products.  So I looked into it.  First of all Licorice has a lot of interesting chemicals in it.  Many of these seem to be good for you.   As long as its used in moderation.  Every silver lining has a cloud.  Licorice contains several different pretty powerful anti-oxidants. Anti-oxidants are important because they protect cells and DNA from oxidative damage. Oxidative damage increases risk of cancer and shortens cell life.   A research team in China, isolated six different compounds from licorice extract.  The licorice compounds were then tested for anti-oxidant and anti-inflammatory properties.   Inflammation can also lead to oxidative damage and can increase risk of heart disease, cancer, diabetes and etc.  Anti-inflammatory agents may protect long-term health.   The compounds are listed below in case anyone wants to look into them a little more deeply.  Interested in making the switch from booze and cigarettes to licorice and tea? New research indicates licorice may be the better choice.

omega-6 fatty acids and health discussion with licorice
CrossFit Trainer talks about nutrition and omega-6 fatty acids and licorice.


All of the compounds had health protective qualities.  Many shared the same properties.  Here are a few of the things licorice extract can do:

  • Anti-Oxidant Power.  Three of the compounds in licorice extract were strong anti-oxidants.  The three were better at scavenging free radicals than Vitamin C.
  • Inhibit Lipid Peroxidation.  A number of the compounds were able to inhibit lipid peroxidation.  Lipid peroxidation damages cell membranes.  Stopping lipid peroxidation is generally considered a good thing.  Licorice compounds also inhibited production of reactive oxygen species.  Reactive oxygen species are compounds that cause oxidative damage including lipid peroxidation.
  • Inhibited prostaglandin E2.  Inhibition of prostaglandin E2 may or may not be a good thing.  Prostaglandin E2 is important in pregnancy and birth.  But it also stimulates tumor growth possibly by increasing inflammation.   It is possible that licorice extracts may be anti-carcinogens.  It is possible that pregnant women should stay away from licorice.
  • Inhibited production of interleukin-6.  Interleukin-6 inhibitors are under study as anti-arthritis drugs.  Interleukin-6 also activates inflammation.  Elevated interleukin-6 is associated with atherosclerosis, depression, diabetes and Alzheimer’s disease, among other things.  Interleukin-6 is important in good ways too.  Inhibiting the hell out of it may create other problems.  Such as maybe suppressing the immune system.

Should I eat tons of Licorice to protect my health?

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Stiff, Inflexible, Invincible WODMasters shirt for the Masters CrossFit Athlete. And for other people who may also be stiff and inflexible.

No.  Don’t eat tons of it.  Licorice has a down side.  Too much of most things is not good and there is not enough research to support going overboard.  There are also compounds in licorice that are harmful.  Licorice has been shown to raise blood pressure, for example.   And there is a case report of a woman who overindulged in licorice (about 1.5 pounds) and became extremely ill.    Her body underwent a series of changes unfavorable to a long life.  To quote from the paper:  Creatine kinase, hypokalemia, hypocalcemia and hypophosphatemia with low aldosterone and plasma renin levels and high intact PTH.  So go light.  She also got rhabdomyelesis.

Should I eat Twizzlers before working out or doing a CrossFit WOD?

You should avoid black licorice if you have high blood pressure.   Otherwise a twizzler or two is probably fine once in a while.  One or two red twizzlers will help you get pumped without the risks posed by black licorice.  And exercise stimulates the body to produce its own anti-oxidants.  Adding anti-oxidants before a workout may blunt your body’s response.  In this case red Twizzlers may be better than black twizzlers as a pre-workout stimulant.  Only black twizzlers are made with real licorice extract.  If you check the package you will see that it contains “less than 3% licorice extract.”  With good quality control you could eat a pound of black twizzler licorice and consume less than 3.6 grams of extract.  The University of Maryland posts that licorice can be used at about 1.2 grams per day.  A pound of twizzlers may contain three times that limit.    Hard to say when the content might be anywhere between 3.6 grams and nothing.  There is a lot of information and a lot of research being done on licorice as a medicinal plant.  Much more than I expected.  More than I can chew right now.   There does not seem to be any research on the benefits or dangers of red twizzlers.

Licorice compounds with anti-oxidant and anti-inflammatory properties:

  • 5′-(1,1-dimethylallyl)-3,4,4′-trihydroxy-2-methoxychalcone
  • licochalcone B
  • licochalcone A
  • echinatin
  • glycycoumarin
  • glyurallin B

Fu Y, Chen J, Li YJ, Zheng YF, & Li P (2013). Antioxidant and anti-inflammatory activities of six flavonoids separated from licorice. Food chemistry, 141 (2), 1063-71 PMID: 23790887

Sigurjónsdóttir HA, Franzson L, Manhem K, Ragnarsson J, Sigurdsson G, & Wallerstedt S (2001). Liquorice-induced rise in blood pressure: a linear dose-response relationship. Journal of human hypertension, 15 (8), 549-52 PMID: 11494093

Shah M, Williams C, Aggarwal A, & Choudhry WM (2012). Licorice-related rhabdomyolysis: a big price for a sweet tooth. Clinical nephrology, 77 (6), 491-5 PMID: 22595392

Hiking: Eccentric Exercise That's Not That Crazy.

Eccentric Exercise is a hot research topic among exercise physiologists.   Most research has focused on concentric exercise.  As often happens, the eccentric is readily overlooked.  Concentric exercise is exercise that involves muscle fiber shortening.  During eccentric exercise muscles are lengthening under stress.   Hiking is great exercise in part because it involves many different types of stresses.  If you are in mountainous terrain it includes both concentric and eccentric exercise.   Hiking (or running) uphill is concentric exercise, while moving downhill is eccentric.Uphill tends to burn more calories than downhill, but it looks like downhill hiking provides special benefits on its own.

Hiking Eccentric Exercise
A Hiker Prepares Mentally for a bout of Eccentric Exercise

Testing Up Hill (Concentric) and Down Hill (Eccentric Exercise) Hiking.

Researchers in Austria and Lichtenstein have been looking at the benefits of hiking down hill.   The study group has also been looking at ways for people to exercise more easily when they either do not have time or are just not interested in doing it.  The studies used two groups of people.  One group hiked only uphill, and the other hiked only down hill.  Hiking only uphill or only downhill may be problematic for most people.  For the study, a cable car was used to transport hikers in the up group down.  And the down group up.  Blood samples were collected before the start of the hiking procedure and afterward.  Hikers hiked in one direction for two months and then switched to the other directions.


Hiking results and findings.

hiking uphill concentric exercise
A hiker rests above 15,000 feet after a little too much concentric exercise and not enough oxygen

Hiking uphill and downhill both improved blood measures of total cholesterol, low-density lippoprotein cholesterole (LDL), apolipproteinB/A1 ratios (by about 11%), insulin resistance and reduced levels of C-reactive protein by ~30%.  Hiking uphill burns more energy.  Hiking uphill requires about 4x as much energy as hiking downhill.

Still, it is nice to know that walking downhill is so healthy.  I find down-hill hiking stresses my knees and toes.  However if you are one of those people who enjoys the downhills don’t worry too much if you hitch rides on cable cars.  Or mules.  Or whatever else is available.  Perhaps this research will result in the development of a new type of fitness equipment: A Stair Descender.

Eccentric exercise is the type of exercise stressor that leads to muscle soreness.  And delayed-onset muscle soreness (DOMS).  But there is increasing evidence that eccentric exercise is more effective for improving muscle strength.


If you are looking for traditional hiking or eccentric exercise options and ideas take a look at:

Zeppetzauer M, Drexel H, Vonbank A, Rein P, Aczel S, & Saely CH (2013). Eccentric endurance exercise economically improves metabolic and inflammatory risk factors. European journal of preventive cardiology, 20 (4), 577-84 PMID: 22505055
Drexel H, Saely CH, Langer P, Loruenser G, Marte T, Risch L, Hoefle G, & Aczel S (2008). Metabolic and anti-inflammatory benefits of eccentric endurance exercise – a pilot study. European journal of clinical investigation, 38 (4), 218-26 PMID: 18339002

Sprint Interval Training. High Intensity Interval Training.

Sprint Interval Training is a training strategy where an athlete goes “all out” for short burst of time.

The terms “Sprint Interval Training” (SIT) and “High Intensity Interval Training” (HIT) are both used by researchers.   SIT/HIT can be short sprints, but it can also consist of short “all out” bursts of other exercises. This exercise strategy is more like CrossFit.  And findings on SIT/HIT can probably be well applied to CrossFit.

Research on SIT/HIT will tell us a lot about what CrossFit does to and for us.  Think Fran and consider the thrusters as the brief rests.  We discussed SIT as HIT in an earlier article.  How good is Sprint Interval Training compared to traditional moderate intensity endurance workouts?  Like running?  Or cycling?

Is Sprint Interval Training or High Intensity Interval Training better than running or cycling?

That question has not been answered yet.  Here’s what is known so far:

  • Both types of training improved aerobic capacity.
  • Both improved insulin sensitivity.
  • And both reduced arterial stiffness.
  • Both forms of training reduce blood glucose levels.

Arterial stiffness is a risk factor for cardiovascular disease.  Like stroke.  Or heart attack.  Sprint Interval Training can be done in a shorter time than traditional running or cycling.  And it can be done without having a safe place to cycle.  Or run.  Measurable improvements in blood glucose can show up in 2 weeks of 3x a week workouts.   Note that “measurable” change is not the same as “will prevent diabetes.”  More work will need to be done on that.Training produces other adaptive responses.  Including “vascular remodelling.”

So far both endurance training and HIT or SIT training improve vascularization.  Excercise increases growth and development of vascular tissue.  Like capillaries.  And increases blood flow to muscles.  A lot of questions remain.  What happens when training tapers off?  Do improvements only happen in muscles exercised?  Would a runner have a great network of veins and capillaries in legs alone?  Would an intense all over workout like CrossFit give the best over all vascular health?  We’ll see what comes up.

Cocks M, Shaw CS, Shepherd SO, Fisher JP, Ranasinghe AM, Barker TA, Tipton KD, & Wagenmakers AJ (2013). Sprint interval and endurance training are equally effective in increasing muscle microvascular density and eNOS content in sedentary males. The Journal of physiology, 591 (Pt 3), 641-56 PMID: 22946099

Little JP, Gillen JB, Percival ME, Safdar A, Tarnopolsky MA, Punthakee Z, Jung ME, & Gibala MJ (2011). Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes. Journal of applied physiology (Bethesda, Md. : 1985), 111 (6), 1554-60 PMID: 21868679

Cocks M, Shaw CS, Shepherd SO, Fisher JP, Ranasinghe AM, Barker TA, Tipton KD, & Wagenmakers AJ (2013). Sprint interval and endurance training are equally effective in increasing muscle microvascular density and eNOS content in sedentary males. The Journal of physiology, 591 (Pt 3), 641-56 PMID: 22946099

CrossFit Fran workout consists of thrusters and pull-ups.

Crossfit High Intensity Interval Workouts

Crossfit – High Intensity Interval Training workouts.

crossfit men discuss womens resistence training
Two ugly crossfit men talk about crossfit, high intensity interval training workouts and WODMASTERS WORKOUT SHIRTS.  Why aren’t they weraing them now?  Get to the shop guys.

Endurance exercise is recommended for cardiovascular health.  Years of research have found that about 30 minutes of cardio will reduce risk of stroke and heart attack.  It will also improve insulin sensitivity, reduce risk of diabetes and improve memory and brain function.  Until very recently, there has been little research on the benefits of CrossFit type exercise on health.  These studies focus on High Intensity Interval Training.  High Intensity Interval Training workouts consist of multiple sets of intense exercise that last 1-4 minutes.  These are spaced with short rest periods.  Or periods of light exercise.

High Intensity Interval Training Workouts with gas mark.
There are so many ways to make life harder. High Intensity Interval Training Workouts can make you hurt faster

Research on this approach to exercise indicates that this approach may number of ways.  These include cardio and respiratory fitness.  And also insulin sensitivity and arterial stiffness.  Arterial stiffness is an indicator for risk of cardiovascular disease.  It is also looking like High Intensity Interval Training may be better at controlling or preventing high blood pressure than the traditional 30 minutes of sustained cardio.

CrossFit Training vs. Running?

The question of is CrossFit better than running is not known yet.  And CrossFit is different than the types of High Intensity Interval Training being tested.  In a nutshell, CrossFit is a fitness program that involves high intensity exercise.  Many different muscle groups are targeted in a CrossFit workout (also known as a CrossFit WOD.)  Workouts may last 5-20 minutes and involve springs, weight lifting, pull-ups and other bodyweight exercises.  If you are wondering “what is CrossFit” try this link. CrossFit exercises may or may not include periods of rest between sets.  However, there is a lot of shifting of focus.  Intensity may be sustained, but not sustained on the same muscle groups.  This might be better for vascular health.

CrossFit High Intensity Interval Training.

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Stiff, Inflexible, Invincible WODMasters shirt for the Masters CrossFit Athlete. And for other people who may also be stiff and inflexible.

Short periods of high intensity interval training type exercise improve capillary growth.  This allows for greater blood flow to tissues.  Including muscle.   It is possible that intense exercise impacting multiple muscle groups would be better than exercise that impacts only legs (as in running). This is an exciting area of research.  It will be interesting to see what comes up next.  Hopefully more research will be done soon that will look at whether or not CrossFit or High Intensity Interval Training does as well with brain health and control of diabetes.  For a look at recent papers take a look at:

Cocks, M., Shaw, C., Shepherd, S., Fisher, J., Ranasinghe, A., Barker, T., Tipton, K., & Wagenmakers, A. (2012). Sprint interval and endurance training are equally effective in increasing muscle microvascular density and eNOS content in sedentary males The Journal of Physiology, 591 (3), 641-656 DOI: 10.1113/jphysiol.2012.239566

Spence AL, Carter HH, Naylor LH, & Green D (2013). A prospective randomised longitudinal study involving 6-months of endurance or resistance exercise on conduit artery adaptation in humans. The Journal of physiology PMID: 23247114

Research Shows CrossFit Diet/Exercise Reduces Risk of Heart Disease." Cool.

“Research Shows CrossFit Diet/Exercise Reduces Risk of Heart Disease”.  An article in Google News had this headline. Could that be true? Probably. A diet low in refined carbohydrates and high in vegetables and fruit, as well as an active lifestyle has long been associated with reduced risk of death and disease. However, no scientific research as been published on relationships between CrossFit training and cardiovascular disease. If one were to do a search today on Web of Knowledge using the search term “Crossfit” you would get a single hit:

Jansen, J., van Dam, N., Hoefsloot, H., & Smilde, A. (2009). Crossfit analysis: a novel method to characterize the dynamics of induced plant responses BMC Bioinformatics, 10 (1) DOI: 10.1186/1471-2105-10-425.

Summer Rogers of CrossFit Seven in Fort Worth is encouraged by a Master CrossFit-ter

I’m sure the intentions of whoever wrote the article (which turned out to be a press release by a box in California. Not sure why they paid to do this but to each his/her own) were good . . . but . . . their interpretation of the research is quite a stretch. Stretching and far-fetchedness probably hurt the cause as much as they help. Still, interesting that it made it into Google News. The research the author discusses has nothing to do with CrossFit. The press release does, however, attempt to associate a high-fat diet with lower incidence of cardiovascular disease by comparing incidence of disease between residents of Switzerland and Australian aboriginals living in modern Australia.

The claim was that a high-fat dining Swiss have less cardiovascular disease than the presumed low-fat dining Australian Aboriginals and that, therefore, high-fat diets are healthier than low-fat diets. There are also obviously many other differences between the Swiss and the Aboriginals (differences in poverty levels, availability of lederhosen and differences in other possibly important variables like intake of strong coffee and chocolate).

I have not looked up the statistics for the Swiss, but Australian Aboriginals have been suffering increasing rates of cardiovascular disease over at least the last 30 years. They are also suffering from increasing obesity and diabetes just like so much of the rest of the world. However, few modern Aboriginals are likely to be following a traditional Aboriginal diet. It is extremely unlikely that the increasing rate of heart disease observed in Australian Aboriginals has been caused by low intake of dietary fat. The increased incidence of cardiovascular disease in Aboriginals may be due to genetic vulnerability and a change to a Western-type diet but extremely unlikely to be caused by a low-fat diet (especially since they are not eating this way anymore anyway).   An Australian aboriginal is still less likely to die from heart disease than an Australian of European ancestry, but that may be in part because Aboriginals are more likely to fall to a violent or accidental death.

The Press release did not provide a reference.  I think this is the original article but I’m not sure.  In any case it has some very interesting things to say if you are interested in learning more about relationships between cholesterol and risk of cardiovascular disease.

Rowley K, Walker KZ, Cohen J, Jenkins AJ, O’Neal D, Su Q, Best JD, & O’Dea K (2003). Inflammation and vascular endothelial activation in an Aboriginal population: relationships to coronary disease risk factors and nutritional markers. The Medical journal of Australia, 178 (10), 495-500 PMID: 12741936

O’Dea K (1991). Westernisation, insulin resistance and diabetes in Australian aborigines. The Medical journal of Australia, 155 (4), 258-64 PMID: 1875844 Petursson H, Sigurdsson JA, Bengtsson C, Nilsen TI, & Getz L (2012). Is the use of cholesterol in mortality risk algorithms in clinical guidelines valid? Ten years prospective data from the Norwegian HUNT 2 study. Journal of evaluation in clinical practice, 18 (4), 927-928 PMID: 22639974