Tag Archives: health

iPhone 4, SAR, and antenna contact

The iPhone 4 uses the metal edge of the phone as its antenna. This means that it’s pretty easy to make contact between the antenna and your hands. As you’ll know if you’ve ever grabbed the antenna of a TV or FM radio, the human body conducts, and can have a pretty big effect on reception.

Users are now reporting that it’s true for the iPhone too. You can lose most of your signal strength by holding the phone the wrong way.

What I haven’t seen anyone discuss yet is the effect on the phone’s Specific Absorption Rate (SAR) caused by the antenna making contact with your hand while the device is transmitting. I know that making contact with a high powered radio mast can cause RF burns, so antenna contact definitely can result in much more energy reaching your body via conduction than you get exposed to by radiation from being next to the antenna. So it seems to me that there will be increased EM exposure from having sweaty fingers in contact with the iPhone antenna most of the time it’s transmitting, and I doubt the standard measurement methods for estimating SAR allow for this factor.

So, does anyone know how SAR levels change if you’re physically in contact with the antenna? Has anyone seen any discussion of this? Apple’s engineers must have thought of this and allowed for it when setting transmission levels, right?

New year reflection

One of IBM’s better ideas is to encourage employees to take part in an active health management program. I just filled out the annual survey, putting in my most recent set of figures for blood pressure, cholesterol levels and so on.

Here’s the result:

I’m mildly surprised. I always feel like everyone else is exercising more diligently than me, is stronger than me, and so on. I wonder if my "peer group" is everyone my age, or just IBM software engineers?

Anyhow, with my back injury pretty much gone, I’m back on the treadmill–or rather, the elliptical. 30 minutes a day 4-6 times a week. I bribed myself with a doughnut yesterday, but that’s not going to be a regular thing, I just need something to get my enthusiasm started and get the momentum going.

Elliptical observations

I didn’t drive until 2004. I relied on public transit to get everywhere. This meant that I thought nothing of walking for half an hour to get where I wanted to be, and then walking back afterwards. Especially if the bus didn’t turn up.

In Massachusetts, I would start to gain weight as winter set in; all my body wanted me to do was eat and stay in bed. But in spring and summer, I’d walk it all off again.

And then I learned to drive, and we got a car and moved to Texas. Now in summertime I find myself glad to get back into the air conditioning after a brief stroll across the parking lot. I started getting heavier in summer, rather than in winter.

Oh, it can be beautiful in fall, winter and spring, especially evenings. But even after concerted effort, I wasn’t getting anything like as much exercise as I used to, and I was gradually getting fatter. Clearly I had to do something.

The traditional solution most Americans favor is to join a gym and not go to it. This gives you the feeling that you’re doing something positive, while still leaving you with all your valuable couch time. However, gym memberships are expensive, and school experiences have left me with an indelible view of locker rooms and gyms as places of ritual torture and humiliation.

Another popular solution is to buy an exercise machine. This has distinct advantages over a gym membership. For starters, it’s a one time expense, which is better than a gym membership if you know you’re just throwing money away. In addition, the machine can be used as a place to hang shirts, ties, and other apparel you’re too lazy to put in the closet where it belongs. And if you need the space, you can do what our last landlord did, and put the exercise machine out in the yard to act as a kind of rust sculpture and casual birdfeeder.

I did some research, and elliptical machines seemed to be the best option. They are low-impact exercise for the cardiovascular system, provide some exercise for the upper body, the machines are quiet, and some of the newer ones are quite small. I found that a local store had a good deal on one, and bribed some friends to help transport it home as the box wouldn’t fit in the car.

Some assembly was required. In fact, putting the device together was a good dose of exercise to start with. Everything seemed to work, including the electronic control panel and the servos that adjust the magnetic resistance, and the next day I tried it out for real.

And much to my surprise, I’ve been exercising pretty much every day since then. It has been one month with the machine, and have skipped exercise on only a couple of days when work and social engagements made it impossible to find a solid block of time. Exercise has become a habit, which I gather is one of the secrets to actually doing it. I now separate work from a relaxed evening by burning off around 2500 kJ. I can listen to radio shows, and I don’t have to interact with strangers in the shower. I’ve dropped 2kg so far.

Mostly for Dan

Researchers at the Harvard School of Public Health analyzed nicotine yield of cigarettes sold in Massachusetts from 1997 to 2005. The result: cigarette manufacturers have been gradually boosting the level of addictive nicotine by an average of 1.6% per year, or 11% over the 7 year period studied.

Something to bear in mind while watching re-runs of the South Park episode “Butt Out“, in which Parker and Stone bravely defend the cigarette corporations for providing a little harmless pleasure to people, who after all smoke of their own free will.

Failures of the free market: food

One of the nice things about the USA is that every food package has a handy table on the back listing the proportions of various nutrients it contains. (It looks like the one on the front page of my web site.) This makes it very easy to look at two cans of soup, and say “Jeez, this one is 34% of my recommended sodium intake for the day, and 20% of my recommended fat… but this one is only 10% sodium and 2% fat.”

The sad thing is, of course, that it doesn’t make any difference to the obesity epidemic.

What we have in food is a failure of the idea of the free market. The problem is, humans evolved in an environment where certain nutrients were difficult to obtain, food supplies were severely constrained, and certain tastes were rare. We therefore evolved particular food preferences. An example is the craving of sweetness, which was once a really good way to motivate us to eat fresh fruit, which is very nutritious but hard to find and retrieve.

Unfortunately, increasing knowledge has allowed us to find other ways to stimulate those desires—so now almost all foods have sugar in, to continue the example. The cravings which used to work so well, now result in us bingeing on the wrong things. We no longer need to store fat to make it through the winter, but potato chips stimulate the “mouthfeel” our primitive ancestors evolved to motivate them. We get plenty of salt and have air conditioning to keep cool, but we still love salty snacks.

So, the free market encourages competition to bring us the most desire-stimulation at the cheapest price possible. The end result is McDonalds. Cheap, nasty food; but oh, so stimulating. For many people it becomes an affordable addiction.

What should we do? Well, we really ought to regulate the free market. If I were supreme ruler, I’d probably decree that no single serving of food be permitted to contain more than half a day’s fat, sodium, cholesterol, and so on. I mean, it’s possible to make delicious pizza that good for you, so why do we let people make the Pizza Hut Stuffed Crust With Extra Cheese pizza?

A single slice of Cheesecake Factory carrot cake contains more saturated fat and cholesterol than you’re supposed to eat in an entire day. Ditto for their chocolate cake. Yet this afternoon I had the most incredible slice of chocolate cake that came in at 18% of a day’s sat. fat. Why are they allowed to get away with it? Aren’t they being as cavalier with our health as the cigarette companies who put in unnecessary nicotine?

Mind you, at least there’s not much danger of passive chocolate cake…

Clean bill of health

Just had my annual physical. Pulse normal, blood pressure 110/75, eyes normal, chest/breathing normal, no sign of hernia (whatever that is).

My weight is slightly lower than ideal, but only slightly, and I like it that way.

In the unlikely event that I have high cholesterol, they’ll contact me.

Oh, and a neGcon I found on eBay arrived. WipeOut 3 weekend!