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.

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REFERENCES

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

Seasonal Allergies in Japan

Japan belongs to the temperate zone with four distinct seasons, and has six principal climatic zones: Hokkaidō (北海道) with long, cold winters and cool summers; Central Highland (中央高地) with typical inland climate and large temperature differences between summers and winters and between days and nights; Seto Inland Sea (瀬戸内海): with mild climate; Pacific Ocean (太平洋): with cold rainy winters and hot humid summers;  Ryukyu Islands (南西諸) with warm rainy winters and hot humid summers. Heat and high humidity can lead to possible food poisoning, fatigue and heat stroke.

More than 5,000 species of plants find home in these diverse climatic conditions and more than 60 types produce pollen that can cause allergic reactions. In Tokyo, common allergy-causing plants and their pollen seasons are as follows:

Japanese cedar sugi (February - April)

Japanese cypress hinoki (mid March - early May)

Rice plant ine (May - mid July / mid August - mid October)

Ragweed butakusa (mid August - October)

Artemisia yomogi (mid August - October)

Japanese Cedar is one of the major causes of seasonal allergic rhinitis and seasonal allergic conjunctivitis (itchy eyes). Its pollen is one of the most potent known and may cause severe symptoms. In Tokyo, about one in 3.5 people is believed to suffer from sugi allergy. The Japanese cedar pollen is present from approximately the end of January until the beginning of April on the north island and mid-April until early May on the south island. The cypress tree flowers a little later than that of the cedar tree and could also contribute to allergies. The pollination of Ragweed begins in late summer, around August, but its impact is less significant than in North America. 

January

February

March

April

May

June

July

August

September

October

November

December

Trees

Grasses

Weeds

See this site by Allergy Research Group, Department of Otorhinolaryngolgy, Jikei Medical School, for more information. Or sign up for Aurametrix and start analyzing your allergies - to control them wherever you go.

How cold is cold enough? How humid is really humid?

How cold is too cold? How windy is really windy? It depends on where you live. If you are from the South you will need a blanket if it's below 50 degrees Fahrenheit (10 °C). If you are accustomed to cold weather, 70 (20+ C) is too hot.  For residents of Oymyakon in Eastern Siberia with average winter temperature of -49°F (−45°C) and record low -90°F (-67.7°C), -30°F (−34.4°C)  is pretty pleasant. If you live in Cold Bay, Alaska, 15 miles per hour is not really windy, while in Oak Ridge, Tennessee average wind blows at only 4 miles per hour.

In general,

110 Fahrenheit is considered dangerously hot

100° F may be hazardous

90° F is uncomfortably hot

80-40 is considered a relatively comfortable range - the average surface temperature of the Earth is 59° F

30° F is uncomfortably cold
15° F is very cold (although for avid runners cold is below 10 F with winds over 15 mph)
0° F is bitter cold with significant risk of frostbite

But let's take a closer look at the world's climate, mostly defined by long-term (30 years) patterns in temperature and precipitation:


Purple regions (A) in this map are hot and rainy year around. Orange areas (B) are dry with little rain and a large range of daily temperatures. Green areas are two-season climates with warm, dry summers and cool, wet winters. Blue regions (C) have continental climates with distinct four seasons and moderate precipitation. E denote cold areas with permanent ice and tundra. Only about four out of twelve months temperature in these areas raises above freezing.

3 most windy cities in US (seasonal wind averages are given in miles per hour):

City                JAN    FEB    MAR    APR    MAY    JUN    JUL    AUG    SEP    OCT    NOV    DEC    ANN

MT. WASHINGTON, NH  46.1   44.3   41.4   35.8   29.7   27.3   25.3   24.7   28.8   33.8   39.5   44.5   35.1

ST. PAUL ISLAND, AK 19.9   20.0   18.8   17.4   14.9   13.6   12.1   13.7   15.4   17.4   20.0   20.1   16.9

COLD BAY,AK         17.5   17.9   17.4   17.5   16.2   15.8   15.6   16.2   16.2   16.6   17.5   17.5   16.8

10 most humid cities in US:
No. 10: Olympia, WA
Average relative humidity: 78%
Average annual precipitation days: 163
Highest precipitation month: November
No. 9: Houston, TX
Average relative humidity: 78%
Average annual precipitation days: 105
Highest precipitation month: June
No. 8: Brownsville, TX
Average relative humidity: 78%
Average annual precipitation days: 73
Highest precipitation month: September
No. 7: Victoria, TX
Average relative humidity: 78.5%
Average annual precipitation days: 91
Highest precipitation month: May

No. 6: Corpus Christi, TX

Average relative humidity: 78.5%
Average annual precipitation days: 77
Highest precipitation month: September

No. 5: Lake Charles, LA

Average relative humidity: 79.5%
Average annual precipitation days: 104
Highest precipitation month: June

No. 4: Port Arthur, TX

Average relative humidity: 78.5%
Average annual precipitation days: 77
Highest precipitation month: September

No. 3: Astoria, OR

Average relative humidity: 81%
Average annual precipitation days: 193
Highest precipitation month: November

No. 2: Mount Washington, NH

Average relative humidity: 83%
Average annual precipitation days: 209
Highest precipitation month: November

No. 1: Quillayute, WA
Average relative humidity: 83.5%
Average annual precipitation days: 209
Highest precipitation month: November 

Highest Average Annual Precipitation Extremes in the World
	Continent	Highest Avg. (Inches)	Place	Elevation (Feet)	Years of Record
	South America	523.6 *	Lloro, Colombia	520	29
	Asia	467.4 *	Mawsynram, India	4597	38
	Oceania	460.0 *	Mt. Waialeale, Kauai, HI	5148	30
	Africa	405.0	Debundscha, Cameroon	30	32
	South America	354.0	Quibdo, Colombia	120	16
	Australia	340.0	Bellenden Ker, Queensland	5102	9
	North America	256.0	Henderson Lake, British Colombia	12	14
	Europe	183.0	Crkvica, Bosnia-Hercegovina	3337	22
* The value given is continent's highest and possibly the world's depending on measurement practices, procedures and period of record variations.