Monday, November 4, 2013

Keeping Pollutants Out with Exercise

Food, drugs, air and everyday products like soap, cloth and grocery receipts are polluting our bodies with hundreds of toxic chemicals. New chemicals are constantly being introduced into our environment and the effects of most of them on human health are not known. About 30% of human diseases are due to environmental exposures as genetics is not the whole story. 

Whether rich or poor, our bodies are burdened with toxic waste. High socioeconomic status means more mercury and arsenic from fancy fish, chemicals from carpet cleaning and sun screens. Poverty is associated with chemicals from  smoking and eating canned food. Besides, high fat diet and other prior exposures make us even more vulnerable and less able to handle the load of toxic waste. 

Intake of toxins from food, drugs and personal care products can be minimized by smarter consumption, awareness and learning - although sometimes we need a pair of earmuffs to filter excessively negative information in the press. But what about the chemicals in the air? Should we try to stay inside residential buildings and limit exercise if we live in urban environments? 
Air pollution and aerobic exercise could be a very unhealthy combination. Pre-workout exposure to polluted air raises heart rates during the workout. During aerobic activity we typically inhale more air through our mouth bypassing the nasal passages, thus not filtering out pollution particles and breathing them more deeply into our lungs. Certainly, people with or predisposed to asthma, diabetes and other chronic conditions might want to avoid spending times outdoors when air is polluted. But for the rest of us, physical activities like walking or biking to work could be OK - if we pedal harder. 

Polluted air can, indeed, promote inflammation, but exercise builds abilities to fight inflammation, making us stronger over time and protecting our bodies from negative effects of pollution. Mild levels of exercise can make us inhale even more polluted air. But if we apply sustainable efforts, our respiratory or metabolic responses are practically the same as in the clean air. Is it because heavier breathing helps us to getting rid of the pollutants before they had a chance to trigger harmful effects? 

Whatever the explanation - exercise is good for you. It is your best defense against pollution. 

Giles LV, & Koehle MS (2013). The Health Effects of Exercising in Air Pollution. Sports medicine (Auckland, N.Z.) PMID: 24174304

Tyrrell J, Melzer D, Henley W, Galloway TS, & Osborne NJ (2013). Associations between socioeconomic status and environmental toxicant concentrations in adults in the USA: NHANES 2001-2010. Environment international, 59, 328-35 PMID: 23892225

Vieira RP, Toledo AC, Silva LB, Almeida FM, Damaceno-Rodrigues NR, Caldini EG, Santos AB, Rivero DH, Hizume DC, Lopes FD, Olivo CR, Castro-Faria-Neto HC, Martins MA, Saldiva PH, Dolhnikoff M. (2012)  Med Sci Sports Exerc. Jul;44(7):1227-34. doi: 10.1249/MSS.0b013e31824b2877. Anti-inflammatory effects of aerobic exercise in mice exposed to air pollution. PMID: 22297803

Sunday, October 20, 2013

Are You What You Read or Do You Read What You Are?

The environment plays a significant role in our health. We are exposed to multiple physical, chemical and biological challenges, including information  - like news and gossip stories related to health and wellness. How exactly is it affecting us?

University of Pennsylvania researchers surveyed over two thousand US adults 40 to 70 years of age on how they scanned for information about specific health behaviors. The researchers followed up one year later to see how participants' behaviors changed. The result?  Consumption of health information does affect specific behaviors. But the effect is not as straightforward or as strong as one might think.

As was shown earlier, people who seek information about particular health issues are typically in the middle of making a decision, and need information to ease anxiety or reinforce confidence in their already made decision. The recent study also shows that people already motivated to change their behavior may be more motivated to scan information about this change of behavior. But exposure to information might not be helpful if they have not made a decision yet.

For example, women actively scanning information about breast cancer after getting a mammogram are more likely to get another one next year compared to those who consume the same amount of information but have not made up their mind about getting a mammogram yet. People that exercise and eat healthy are more likely to continue doing so one year later than those not adhered to healthy behaviors yet, despite the same amount of health-related information consumed during the past year.

Online content discovery platform Outbrain did their own research and found similar if not more dramatic results. Analysis based on total U.S. page views across Outbrain’s network of 100,000+ publisher sites during the month of June 2013 as well as data from the external sources is captured on the figure. Surprised? Health content consumption actually positively correlates with unhealthy weight.

The more obese people live in the region, the more they read online about health. Reading a lot about jobs does not lower unemployment rates either. Information about relationships does help to avoid divorce though. So reading can be good for you. But not sufficient. After all, it was Albert Einstein who said -  Any man who reads too much and uses his own brain too little falls into lazy habits of thinking.


Hornik R, Parvanta S, Mello S, Freres D, Kelly B, & Schwartz JS (2013). Effects of Scanning (Routine Health Information Exposure) on Cancer Screening and Prevention Behaviors in the General Population. Journal of health communication PMID: 24083417

Bennett, A. 7 Surprising (or not?) Facts about the Content Americans Consume. Outbrain blog. October 16, 2013

Wednesday, September 11, 2013

Asthma in September

Asthma sufferers know that when it rains it spores - as fungi and mold get moving through the air. But many don't realize that the most dangerous month for children's asthma symptoms is dry September.

A study of hospital data in New York City found the spike in admissions in two to three weeks after the return to school. Additional New York studies indicated that cold and dry weather in autumn mostly increased admissions in the school-aged population (<18), while hot and dry weather in the summer caused spikes in asthma admissions across all ages. Doctor visits increase every September in many Northern Hemisphere countries. It happens in the United States, the United Kingdom, Mexico, Israel, Finland, Trinidad, and Canada, where 20% to 25% of all childhood asthma exacerbations requiring hospitalization have occurred in September.

Asthma hospitalizations in children 2-15 years in Canada

As students return to school, they are exposed to an increased number of indoor allergens, irritants and health risks. The "flu season" is approaching, weed pollen is not over yet, and indoor air is filled with pests, mold,
dust mites, animal dander, chalk
dust, cleaning agents, scented and unscented
personal care products and fumes.

So what can you do to manage asthma at school? Home environment is easier to control, but if you know your triggers, you can develop a plan - like asking teachers that pet animals with fur and feathers are not kept inside classrooms, dry-erase boards or " dustless" chalk are used instead of regular chalk and making sure that kids with asthma have reliable friends that can support them. 


Sears MR, & Johnston NW (2007). Understanding the September asthma epidemic. The Journal of allergy and clinical immunology, 120 (3), 526-9 PMID: 17658590

Lin S, Jones R, Liu X, & Hwang SA (2011). Impact of the return to school on childhood asthma burden in New York State. International journal of occupational and environmental health, 17 (1), 9-16 PMID: 21344814

Lee CC, Sheridan SC, & Lin S (2012). Relating weather types to asthma-related hospital admissions in New York State. EcoHealth, 9 (4), 427-39 PMID: 23224756

Choi IS, Lee SS, Myeong E, Lee JW, Kim WJ, Jin J. (2013) Seasonal variation in skin sensitivity to aeroallergens. Allergy Asthma Immunol Res. 2013 Sep;5(5):301-8. doi: 10.4168/aair.2013.5.5.301.

Bates DV, Baker-Anderson M, Sizto R. (1990) Asthma attack periodicity: a  study of hospital emergency visits in Vancouver. Environ Res 1990; 51:51-70.

Weiss KB. Strachan D, Hansell A, Hollowell J, McNiece R, Nichols T, Anderson HR, et al. (1999) Collation and comparison of data on respiratory disease. Report to the Department of Health, August 1999.

Rosas I, McCartney HA, Payne RW, Calderon C, Lacey J, Chapela R, et al. Analysis of the relationships between environmental factors (aeroallergens, air pollution, and weather) and asthma emergency admis­sions to a hospital in Mexico City. Allergy 1998;53:394-401.

Garty BZ, Kosman E, Ganor E, Berger V, Garty L, Wietzen T, et al. Emergency room visits of asthmatic children, relation to air pollution, weather, and airborne allergens. Ann Allergy Asthma Immunol 1998; 81:563-70.

Harju T, Keistinen T, Tuuoponen T, Kivela S-L. Seasonal variation in childhood asthma hospitalizations in Finland, 1972-1992. Eur J Pediatr. 1997;156:436-9.

Monteil MA, Juman S, Hassanally R, Williams KP, Pierre L, Rahaman M, et al. Descriptive epidemiology of asthma in Trinidad, West Indies. J Asthma 2000;37:677-84.

Thursday, July 4, 2013

The Hazards of Working Nights: for breasts and beyond

The jury is still out whether Angelina's choice is brave or fearful, but the fact remains: having or not having the "bad" genes is not enough to develop or avoid developing breast cancer. As a matter of fact, only 5% to 10% of breast cancer cases result directly from inherited gene defects. Check it yourself, by using this decision tool developed in Stanford.  Even though for members of some families with BRCA mutations the risk may be as high as 80%, this could be because of environmental exposures and behavioral habits "running in the family". What are they?

Among the controllable risk factors are hormone therapy, birth control pills, drugs (like DES discontinued in the 70s), the use of alcohol (if 2 or more drinks per day), heavy smoking since early age, gaining weight after menopause, exercising less than 1-2 hours per week,  certain cosmetics and personal care products, pesticides (such as DDE), PCBs (polychlorinated biphenyls) and other environmental exposures.

One of such exposures is working at night. And Kristan Aronson's team from Queen's University showed that the risk is not limited to nurses, as in most previous studies.

The study examined over 1000 breast cancer cases vs about the same number of healthy cases, matched by age in Vancouver, British Columbia and Kingston, Ontario.  It found that breast cancer risk was twice higher with 30-plus years of night-shift work versus people that did not have night-shift jobs. The risk is more than three times higher for those working at nights in the health care field. But people working at nights or having rotating schedules for shorter duration of time seem to be unaffected.

Why would staying awake after dark for many years be hazardous to health? Perhaps because of the lack of Melatonin. This hormone is produced naturally by our brains when lights go out, to make us less alert and prepare us for sleep. The more daylight exposure versus night time darkness, the better. Melatonin might help the body in many different ways - for example, by downregulating some of the hormones influencing tumor growth or by exhibiting anti-oxidant and immuno-enhancing properties.
Night shifts are also associated with increased stress and a plethora of health conditions as seen from the number of sick leaves people take, periodontal index (measure of oral health), glucose tolerance, number of heart attacks and strokes, cases of IBS and internal cancers. Actually, night time work was shown to increase the risk of cancers even more than exposure to exhaust fumes.

But this is all statistics. Individual cases can certainly break the mold. Yet, it's summer, so let's make the most of natural light.


Grundy A, Richardson H, Burstyn I, Lohrisch C, Sengupta SK, Lai AS, Lee D, Spinelli JJ, & Aronson KJ (2013). Increased risk of breast cancer associated with long-term shift work in Canada. Occupational and environmental medicine PMID: 23817841

Hansen J, Lassen CF Nested case-control study of night shift work and breast cancer risk among women in the Danish military Occup Environ Med 2012; DOI: 10.1136/oemed-2011-100240.

M S Wolff and A Weston. Breast cancer risk and environmental exposures. Environ Health Perspect. 1997 June; 105(Suppl 4): 891–896. PMCID: PMC1470027

Madigan MP, Ziegler RG, Benichou J, Byrne C, Hoover RN. Proportion of breast cancer cases in the United States explained by well-established risk factors. J Natl Cancer Inst. 1995 Nov 15;87(22):1681–1685.

Monday, March 18, 2013

Blood and Taxes

Nothing is certain, but blood pressure does increase in the end of  winter and beginning of spring. According to Aurametrix users and google statistics. As a matter of fact, it highly correlates with tax fever - as found by Google Correlate algorithm comparing millions of web queries  - see the figure on the right with searches for property taxes shown in red. Or check it yourself!

But the reason for raising blood pressure is not always taxes. Seasonal variation in blood pressure was noticed and described more than 50 years ago and was connected to periods of decreasing outdoor temperature. It happens to healthy individuals and those who suffer from high blood pressure, especially in the elderly.
The figure shows fluctuations in blood pressure observed by French researchers in a large study of 9294 65+ old residents of Bordeaux, Dijon, and Montpellier. Both systolic and diastolic parts of blood pressure as well as heart rate measurements significantly differed across the seasons with a clear trend for increase in colder months. And decreases following warmer weather - the higher the temperature, the larger the blood pressure decreases. Changes in blood pressure relative to outdoor temperature were largest in the elderly (80+ years old).  On average, for a 15°C decrease in outdoor temperature, Systolic blood pressure (SBP) increased 0.8 mm Hg in those aged 65 to 74 years compared with 5.1 mm Hg in the oldest group (≥80 years). For a 15°C increase in temperature, SBP decreased 9.9 mm Hg in the youngest group vs 13.8 mm Hg in those 80 years or older. Winter increases in blood pressure did not seem to be caused by increased alcohol consumption and decreased activity. Neither were they dependent on the indoor temperatures - spending over 12 hours in warm rooms did not help.

The inverse correlation of blood pressure and outdoor temperature is even stronger for "apparent temperature"- aka the perceived coldness derived from the combination of temperature and wind. And it was observed all over the world - as documented in studies performed in US, Denmark, China, Japan... Possible explanations include direct thermoregulation-mediated vasoconstriction, hypothalamic-pituitary-adrenocortical axis (HPAA) and sympathetic nervous system (SNS) activation, sodium/volume retention and impaired endothelial-dependent vasodilatation.  Reduced sleep duration or quality could be also contributing.

Environmental hypertensionology is a very young science. Many things in our environment can cause high blood pressure. The exact mechanisms are not well understood, but systems like Aurametrix could utilize the wealth of empirical evidence and use it for prediction and prevention.

The high blood pressure season is almost over. Fortunately, many critically ill people made it through and, hopefully, learned more. Let's gear up to make the next time easier.



Alpérovitch, A. (2009). Relationship Between Blood Pressure and Outdoor Temperature in a Large Sample of Elderly IndividualsThe Three-City Study Archives of Internal Medicine, 169 (1) DOI: 10.1001/archinternmed.2008.512

Halonen, J., Zanobetti, A., Sparrow, D., Vokonas, P., & Schwartz, J. (2010). Relationship between outdoor temperature and blood pressure Occupational and Environmental Medicine, 68 (4), 296-301 DOI: 10.1136/oem.2010.056507

Brook RD, Weder AB, & Rajagopalan S (2011). "Environmental hypertensionology" the effects of environmental factors on blood pressure in clinical practice and research. Journal of clinical hypertension (Greenwich, Conn.), 13 (11), 836-42 PMID: 22051429

Saturday, February 9, 2013

Will you get the flu this season?

Worst of flu season may be over. But you can still catch a chill. If you shake hands with lots of sick people, for example. Or don't keep sufficiently warm. Yes, your mother has told you, and you thought it was just an old wives' tale, but it wasn't. Scientists (Johnson and Eccles, 2005) provide evidence that cold exposure may induce cold symptoms without any contact to sick individuals. As we all carry dormant (sub-clinical) infections in our nose, genitals and other parts of the body, and these viruses may get reactivated. Ever noticed the need to blow nose after spending some time in cold air? Your body might be trying to expel the waking-up microbes.

Emerging health analysis software tools like Aurametrix aim at keeping us healthy by warning about symptoms and diseases. Prolonged exposure to cold means that 4-5 days after the exposure there is 10% probability of developing nasal stuffiness, sneezing, throat irritation of mild fever. 10% if Aurametrix knows nothing else about you. Higher if you are in the most vulnerable age & health conditions group, have a history of more frequent cold infections in prior years or were recently exposed to other stressors. Aurametrix can draw additional conclusions from looking at ingredients in your diet and chemicals in your environment.  Medical records could add another thousand variables. Medical codes given to every documented complaint, prior medications, procedures, information about attending doctors and payments were shown to help predict C.difficile infections in hospitals using machine learning (Wiens, Guttag, Horvitz, 2012).

Social media (in addition to notifications by official sources) keeps us more aware and more afraid of the flu. But what if we are not able to keep away from exposure to a virus, forgot to clean our hands and could not avoid a non-ventilated area with sneezing sick people? The good news is that if we did everything else right we have a fighting chance. As it was shown in a scientific study (Huang et al., 2011), only 9 out of 17 healthy human volunteers exposed to H3N2 virus developed mild to severe symptoms.

So be happy to be healthy, in addition to doing your best to stay flu-free.

Image Credits: Allison Morris,  Flu Infographic


Johnson C, & Eccles R (2005). Acute cooling of the feet and the onset of common cold symptoms. Family practice, 22 (6), 608-13 PMID: 16286463

Jankowski R, Philip G, Togias A, Naclerio R. Demonstration of bilateral cholinergic secretory response after unilateral nasal cold, dry air challenge. Rhinology 1993; 31: 97-100

J. Wiens, J. Guttag, E. Horvitz. Learning Evolving Patient Risk Processes for C. Diff ColonizationMachine Learning for Clinical Data Analysis, ICML 2012, Edinburgh, Scotland, June 2012.

Huang Y, Zaas AK, Rao A, Dobigeon N, Woolf PJ, Veldman T, Øien NC, McClain MT, Varkey JB, Nicholson B, Carin L, Kingsmore S, Woods CW, Ginsburg GS, & Hero AO 3rd (2011). Temporal dynamics of host molecular responses differentiate symptomatic and asymptomatic influenza a infection. PLoS genetics, 7 (8) PMID: 21901105