Overweight? Why Exercise Doesn’t Help Everyone

Image of a man using an elliptical exercise machine.

Exercise Resistance–It’s Real and Makes Losing Weight Much More Difficult

Have you ever felt as if you work out at the gym, jog, and exercise frequently at home but never seem to lose the amount of weight you want? The cause might be high levels of a liver enzyme called selenoprotein-P, according to Dr. Hirofumi Misu and his colleagues, of Kanazawa University in Japan.

Misu and the researchers on his team conducted a study of mice and people that showed the presence of selenoprotein-P seems to be associated with tiring from exercise faster and receiving fewer benefits from it in terms of weight loss than a control group did. This is a condition called exercise resistance.

No, it’s not just in your head.

It is typically recommended that adults should exercise enough to elevate their heart rate for at least 30 minutes, five days a week, or do intense aerobic exercise for 15 minutes a day, five days a week, to stay healthy. This works beautifully for some people; fifteen to twenty percent of others just feel like they’re dying and so exercise less than the recommended amount or forgo exercise entirely. For such people, their bodies might actually be telling them that exercise isn’t a good weight-loss strategy for them.

Exercise resistance and reduced exercise endurance arise from the relationship between selenoprotein-P and AMPK (adenosine monophosphate-activated protein kinase). AMPK is a protein found in all the cells of a person’s body. When a person exercises, AMPK normally generates energy by causing it to be released from ATP (adenosine triphosphate), which allows a person to feel less tired from exercise and to thus exercise longer and to burn more fat from that exercise. But Misu and his colleagues discovered that, when they injected their wild-type mice with selenoprotein-P and then subjected them to a month of scheduled exercise, the mice’s high levels of selenoprotein reduced their bodies’ use of AMPK, which in turn reduced the amount of energy released from ATP in their muscles and consequently reduced the amount of fat burned. The end result was poor benefit from the exercise.

If selenoprotein-P is such a buzz-kill for exercise, what does it do for us? Selenoprotein-P is thought to be an antioxidant that possibly protects us from poisoning by heavy metals, and it might aid in physical and neural development. Biochemists, however, are not entirely certain of its function.

If exercise can’t work for you, how can that situation be changed?

Therein lies the problem. Though researchers have identified selenoprotein-P as a likely barrier to weight loss through exercise, they haven’t yet developed a way to reduce its presence. They hope that their study results will prompt research into creating drugs that can reduce the amount of selenoprotein-P secreted by the liver. This would enable people with exercise resistance to feel less fatigued from exercise and to gain more healthful benefits from it, particularly in the treatment of type 2 diabetes and metabolic syndrome.

Until that time comes, however, you aren’t off the hook. Lay off the carbs and the sugar, drink water, and control your portion sizes.

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Understanding Your Eye Report

USN Lt. Commander Tyler Miles talks to a patient about his eye condition.

Suppose you recently had an eye examination.  The doctor explained to you what was happening with your eyes, but that was several weeks ago, and you’ve slept since then.  Now your children want to know what the doctor diagnosed.  This article will explain in simple steps what the parts of an eye report are and what certain results mean.  I will start by naming the usual sections seen in an eye report.

Presenting Complaint or Condition:  This is the reason why the patient came to see the doctor on that date.

Brief History:  This lists the patient’s most prominent medical conditions as they relate to eye health.  Sometimes a condition not directly related to vision will be listed if it is affecting vision.  For example, diabetes is a malfunction of the pancreas, not of the eyes, but if it is causing eye problems, the doctor will mention it as well as the patient’s age at onset.

Review of Systems:  The doctor’s assessment of how every part of the patient’s body functions, from the mind, to the muscles, bones, nerves, digestion, and so forth.  Not all eye reports contain this section.

Visual Acuities (VA):  A measurement of how well the patient can see.  This is typically given in measurements according to the Snellen eye test—the usual eye chart with the large E on the top row.  Visual acuities are given for each eye, sometimes at near and always at distance.  Some eye reports also contain fields for unaided visual acuities and for best-corrected visual acuities.  This means the patient’s best vision with and without regular eyeglasses.

Muscle function and intraocular pressure (IOP):  Muscle function describes how the muscles of a patient’s two eyes work together.  Intraocular pressure is a measure of the pressure inside the patient’s eyes, given as a value measured in milliliters of mercury (mmHg) for each eye.

Color vision and photophobia:  After childhood these sections are often marked as ‘not tested’ unless a patient complains of color vision loss or excessive sensitivity to light.  Values for contrast sensitivity might also be found in this section.

Visual Fields (VF):  This gives the measurement of how much of the retina a patient can see with, for both eyes.

Diagnosis:  This is what the doctor concludes, after a thorough examination, is the current state of the patient’s vision or the cause of any noted vision loss.

Prognosis:  The doctor’s prediction of the duration of the patient’s eye problem as well as the expected long-term status of the patient’s eye condition.

Recommendations:  Here the doctor will indicate what should be done to treat or to alleviate the diagnosed condition.

Conclusion:  One of several possible general statements attesting to the patient’s overall eye condition.  This section might or might not be present on an eye report in this exact format.

So what do all of the results next to these section headings mean in relation to your eye report?  Here is a brief guide to some of the more common results seen in the eye reports of people who are suffering vision loss.

Presenting Complaint:  This might be something as vague as “blurry vision” or “Patient states she bumps into things.”  It could also include seeing flashes of light in the eyes or seeing floaters (little shadowy specks).

Brief History:  This might contain a comment such as, “Patient six months s/p laser surgery for glaucoma.”  S/P means “status post.”  The patient’s status is that of having had laser surgery six months before.  Pre-existing, known eye conditions will also be listed here.

Review of Systems:  The most common note for this section will be either WNL (within normal limits) or “Unremarkable,” which means the same thing.  If something remarkable is going on with the patient, the doctor will note it here.  For example:  “EYES:  Ocular prosthesis, right eye.  No discharge from socket.”  Sometimes, under allergies, the doctor will note NKDA.  This means “No known drug allergies.”  The notation PERRLA in the eye section indicates the pupils’ relative size and responsiveness.  It means “Pupils equal, round, reactive to light and accommodation.”  Unequal pupil size or unresponsiveness can be indicators of serious health problems.

Visual Acuities:  The common measurement given for normal vision is 20/20.  Sometimes doctors might use a different numerator, such as 5.  To get the Snellen equivalent for fractions using that numerator, multiply it and the denominator by 4, which, in the case of 5/40, would indicate a Snellen acuity of 20/160.  This means that, what a person with normal vision can read from 160 feet away, the patient with this acuity must read from at most 20 feet away.

Sometimes, instead of writing out the words right eye or left eye, a doctor will use the Latin abbreviations OD, OS, or OU.  OD means “oculus dexter” (right eye).  OS means “oculus sinister” (left eye), and OU means “oculus unitas” (both eyes).  You might also see LE and RE.

Depending upon what state the patient lives in, visual acuity of 20/70-20/199 in the better eye typically indicates at least vision impairment, while visual acuity of 20/200 or worse in the better eye indicates legal blindness.  LP means “light perception,” and NLP means “no light perception.”  BTL (Blinks to light) is also sometimes used, as is HM (hand motion) at X feet or inches.  A person whose best vision is hand motion is considered to be legally blind.  State agencies use visual acuities and visual field measurements together to determine eligibility for state-sponsored blindness rehabilitation services.

Muscle function and intraocular pressure:  If the doctor states that muscle function is abnormal, the cause is likely to be noted as either nystagmus (rapid jerking of the eyes) or some type of strabismus (deviation of one or both eyes from the object being looked at).  Strabismus can be described as esotropia (eye turned toward the nose), exotropia (eye turned toward the side of the face) or hyperopia (eye turned upward).  It can also be constant or intermittent, and it can be congenital or acquired.  Nystagmus too can be present from birth or acquired following trauma, such as a head injury.

The normal range for intraocular pressure (IOP) is 12-22mmHg.  Anything higher than that puts the patient in danger of glaucoma, which causes damage to the optic nerve by the increased pressure literally squeezing and killing the optic nerve fibers, one by one, from the outer edge of the optic nerve bundle toward the middle.  If the pressure is high, but the doctor sees no signs of glaucoma damage, this is called ocular hypertension.  Too low a pressure (10 mmHg or less) is an indication of hypotony, which can occur after a surgery.

Color vision and photophobia:  If the patient is experiencing loss of color vision or photophobia the doctor will simply indicate what colors the patient can no longer see or will mention that the patient is sensitive to light and to how much light.  “Could not tolerate normal room lighting; requested that lights be dimmed.” might be noted.

Visual Fields:  In this section a doctor will typically note, “Some field restriction peripherally,” or “Moderate field restriction inferiorly.”  “Peripherally” refers to the edge of the visual field, and “inferiorly” refers to the lower half of the visual field.  Sometimes the doctor might mention a field loss medially or laterally.  “Medially” means the field loss is toward the nose, and “laterally” means the loss is toward the side of the face.  “Central scotoma” means a blind spot in the central vision, a sign of macular degeneration.  “Scattered scotomata” means the patient has tiny blind spots scattered all over the field of vision, sometimes a result of glaucoma.  The patient might not notice these, but the loss will show up on a visual field test.

State rehabilitation agencies prefer to have the measurement of this loss given in degrees, something to keep in mind if the purpose of a visit is to determine eligibility for rehabilitation services.  A test result of 20 degrees or fewer of visual field indicates legal blindness, even if acuity in that tiny space is 20/20.  It means the patient cannot see well enough to get around without using a white cane to detect where obstacles and drop-offs are.

Diagnosis:  Some common abbreviated diagnoses include CVI (cortical vision impairment), which is primarily diagnosed only in children or in adults who have suffered a brain injury without damage to the eyes, ROP (retinopathy of prematurity), a condition present at or shortly after birth, RP (retinitis pigmentosa), a genetic condition leading to progressive loss of peripheral vision that can result in total blindness, DR (diabetic retinopathy), POAG (primary open-angle glaucoma), or ARMD (age-related macular degeneration), destruction of central vision in some aging patients.

Prognosis:  For duration of the condition, values can include permanent or temporary, while status descriptions of the eye condition itself can include stable, can be improved, progressive, deteriorating, or guarded, among others.

Recommendations:  In this section the doctor might give a prescription for eyeglasses, prescribe preferential seating or large-print materials at school, or order a low-vision examination with low-vision aids, mobility training, and/or access to para-transit services.  The date of the expected return visit will also be put here, such as, “RTC (Return to clinic) in six months.”

If the patient receives a recommendation for eyeglasses, the doctor will also provide a spectacle prescription form with a lot of numbers that have a plus or a minus sign in front of them.  Minus signs indicate nearsightedness, and plus signs indicate farsightedness.  The numbers describe how much correction the patient needs.  The greater the number is than zero, the worse the patient’s vision is.  So +2.75 indicates a correction for farsightedness, and -2.75 indicates a correction for nearsightedness to the same degree.  But a person with a spectacle prescription of -4.00 is much more nearsighted than someone with a prescription of -1.00.

Prescriptions for eye drops or pills might be given in normal English or in Latin abbreviations.  Common Latin abbreviations might include “One drop in each eye b.i.d (twice a day) or q.d. (each day).  The abbreviation q.i.d. means, “four times a day.”  T.i.d. means, “three times a day.”  P.O, Latin for per os, means “by mouth.”  The term n.p.o (non per os), means “nothing by mouth” and is usually directed for patients about to undergo surgery.

Conclusion:  To wrap it all up, an eye report will often give a form statement such as, “This patient has a serious vision loss, after correction, in a clinical setting,” or “This patient has no vision loss,” or “This patient appears to have no vision.”

I hope this article has made eye reports less mysterious to you and that it helps you have a better understanding of whatever your eye condition might be so that you can manage it in as healthy a way as possible.