Many things automatically happen in a body when activity begins and continues.  While most responses are similar, they do vary from person to person.  The potential for variations in those responses increases greatly when medication and other substances enter into the picture.  The following is a generalized article reviewing those expectations.





A Medications Primer

A Body’s Physiological Response to Activity and Medications / Substances

By Ruth Sova


Many clients in water programs regularly take medications (prescribed and over the counter) or ingest other substances (alcohol, nicotine, caffeine) that may affect the body’s response to activity. (Vigorous exercise can actually increase the effect of certain medications and decrease the effect of others.)  Aquatic practitioners should ask clients about medications used and other relevant health history prior to activity. Practitioners should also be alert to clients who display abnormal response to activity during program monitoring. Not all clients will react the same to a given medication. Dosage, body size, age and sex and the time the drug was administered will all affect the body’s response, as will possible combinations of medications.


   Practitioners should be aware of the purpose of medications and what common side effects to expect with activity.  The purpose of the medication may be to decrease angina pain but the response to activity might increase or decrease blood pressure, blood sugar, or body fluid retention; it may create dizziness, drowsiness, confusion, nervousness, or dryness in the mouth or throat; it may increase or decrease blood volume, elicit early muscular fatigue, decrease lung capacity or circulation; or the inability to obtain a training heart rate; or it could cause migraines or muscle cramping.


   Medication may be referred to by its manufacturer’s trade (or brand) name or by its scientific/generic name, which is also called the drug name. For instance, in the classification of Beta Blockers, Inderal is a trade (or brand) name of one particular type. The generic drug name is propranol. Practitioners should find out the specific medication and determine the general classification that it belongs in to assist in tailoring a program to meet client’s needs. If you are not a medical professional insist on medical clearance for anyone who has a preexisting medical condition or who is taking medication regularly.


     ACE Inhibitors (Angiotensin-Converting Enzyme), are used to control mild to moderate hypertension. These antihypertensives prevent brain impulses from signaling the arteries to constrict and thus prevent an increase in blood pressure. By blocking the angiotensin-converting enzymes that affect arteries, the arterial walls throughout the body are relaxed which, in turn, lowers the blood pressure.  This reduces the workload to the heart and improves its performance.

     Simply put, the antihypertensives known as vasodilators affect the smooth muscle of the arteries in a relaxing fashion.  Ace Inhibitors (angiotensin I-converting enzyme) stop the enzyme responsible for conversion of angiotensin I to angiotensin II. 


     Dizziness, moderate fatigue, and light-headedness when rising are common side effects.  Back pain is a rare side effect. Hypotension (a sudden fall in blood pressure) can easily occur with clients on these medications if they fail to cooldown properly after the workout.  Clients who experience dizziness, lightheadedness or even fainting are experiencing hypotension. 


     These drugs may increase, decrease, or have no effect on the heartrate response.  Although they lower blood pressure at rest, the effect on working heartrates is often unpredictable.


     They include benazepril (Lotensin), captopril (Capoten), enalapril (Vasotec), fosinopril (Monopril), lisinopril (Prinivil, Zestril), quinapril (Accupril) and ramipril (Altace).


     Angiotensin II Receptor Antagonists, called AT II, are used to treat moderate to high hypertension. This drug binds to the AT1 receptor and controls blood pressure by helping the blood vessels stay open. Vasoconstriction and cardiac stimulation are partially blocked. Angiotensin II inhibitors are used not only as antihypertensives, but also to prevent heart failure. 


     Muscle cramps, leg pain, dizziness, fatigue and increased heart rate are possible side effects.

     Angiotensin II Receptor Antagonists include losartan (Cozaar), irbesartan (Avapro), and valsartan (Diovan).


     Beta-Adrenergic Blocking Drugs, called Beta Blockers, are used to decrease hypertension and effort-induced angina.  They work by blocking some of the sympathetic nervous system responses (stress hormones adrenaline, epinephrine, and norepinephrine at sites called beta receptors in heart cells and some blood vessels) which reduce oxygen demands and blood vessel wall contraction.  The reduced oxygen demands by the body are a result of the decreased rate and contraction force of the heart.  When the blood vessel wall contraction is lessened the relaxation and expansion increase, consequently lowering blood pressure. 


     More simply put, Beta Blockers prevent stress-induced increases in the heart rate and will also reduce the force of heart contractions as well as preventing an increase in blood pressure.  When the drugs reduce the heart’s contracting power, it leads to a reduction in cardiac output.  They reduce the resting, working and recovery heart rates by blocking the effects of adrenaline, epinephrine and norepinephrine.  The heart rate may be reduced by as much as 10 to 15 beats per minute. 


     There are two types of Beta Blockers: common beta blockers and beta-adrenegic blocking agents with intrinsic sympathomimitec activity (ISA), which are often used as treatment for angina pectoris, high blood pressure, abnormal heart rhythm, and migraines.


     Beta Blockers with ISA decrease the resting heart rate less than beta blockers without ISA.  Beta Blockers can lessen the ability of the body to respond to the higher working heart rates.  Common side effects are low blood pressure and complaints of fatigue and loss of energy and impotence in men. 


     Long term use of Beta Blockers can decrease heart rate reserve.  Possible side effects are an increased likelihood of asthma in predisposed clients, fluid retention, and a decreased heart rate.  During exercise watch for light-headedness, fatigue, and muscle cramping.  Eliminate isometric contractions from the workout.


      Clients who take Beta Blockers must be cautious and plan to work at a lower heart rate.  The relationships between exercise intensity, oxygen consumption, heart rate and perceived exertion are altered significantly by beta blockers.  The exerciser’s heart rate should be calculated at 10 to 15 beats per minute lower than the average exercise target heart rate.  The monitoring of perceived exertion should be encouraged. 


     Metoprolo (Lopressor) is often the choice for diabetic and asthmatic clients who have hypertension.  Expect fatigue, lethargy and a decreased heart rate.


     Propranolol (Inderal) nadolol (Corgard) and timolol (Blocadren) are all used for clients with migraine headaches or arrhythmia.  Expect the same side effects common to the other Beta Blockers.


     Caruedilol (Coreg) is often used for heart failure.


     Atenolol (Tenormin) and others can cause weight gain.


     Beta Blockers include acebutolol (Sectral), atenolol (Tenormin), betaxolol (Kerlone), bisoprolol (Zebta), bisoprolol/hydrochlorothiazide (Ziac), careudilol (Coreg), carteolol (Cartrol), labetalol (Normodyne, Trandate), metoprolol (Lopressor), nadolol (Corgard), penbutolol (Levatol), pindolol (Visken), propranolol (Inderal), and timolol (Blocadren).


     Calcium Channel Blocking Drugs, called Calcium Blockers, are used for clients with angina and hypertension.  Calcium influx into the arterial muscle tissue to cause concentration and relaxation, thus vasodiolation/constriction (at sarcomere level).  Calcium channel blockers prevent calcium from moving into the artery walls.  These drugs slow electrical activity in the conduction system of the heart and inhibit the contraction of coronary arteries and peripheral arterioles by blocking normal calcium movement.  This reaction prevents spontaneous coronary artery spasm, reduces the rate and contraction force of the heart during exertion, lowers oxygen needs of the heart muscle, reduces the occurrence of effort-induced angina, and reduces contraction of peripheral arterial walls, resulting in relaxation and consequent lowering of blood pressure.


     Possible side effects common to all Calcium Blockers include a variable effect on heart rate response to effort, a decreased or increased heart rate at rest, specified dependent edema, and heart rhythm disturbances.  Avoid excessive exercise with these clients since they can be more active than usual while angina pain is masked.  Expect earlier fatigue.


     Nifedipine (Adalat and Procardia) side effects may include an increased heart rate, swelling of the feet and ankles, and profuse sweating.


     Verapamil (Calan and Isoptin) is also used for arrhythmia and side effects may include an increased heart rate, swelling of the feet and ankles, constipation, and profuse sweating.


     Diltiazem (Cardizem) may decrease the heart rate response and increase fluid retention.


     Nifedipine and diltiazim are preferred over verapamil for people who exercise because they preserve cardiac contractibility.  Calcium Channel Blockers reduce the amount of oxygen demanded by the heart muscle and therefore may actually increase the participant’s exercise performance.


     These drugs may cause hypotension, dizziness, and edema.   An elongated cooldown and the possibility of support stockings can assist clients who take these drugs.  Conservative practitioners will calculate the target heartrate downward approximately 10 to 15 beats per minute and closely monitor perceived exertion for these clients.


     Calcium Channel Blockers include bepridil (Vascor), diltiazem (Cardizem), felodipine (Plendil), isradipine (DynaCirc), nicardipine (Cardene), nifedipine (Adalat, Procardia), nimodipine (Nimotop), norvasc (Amlodopine), and verapamil (Calan, Isoptin).


     Diuretics are used to decrease fluid retention associated with congestive heart failure, liver disease or kidney disease, and lessen edema.   Diuretics increase removal of salt and water from the body through increased urine production.  This reduces sodium and volume of fluid in the blood.


 Diuretics are thought to help clients with high blood pressure by both relieving water and sodium retention and dilating arteries to assist blood flow. Furosemide (Lasix) is often prescribed to decrease hypertension. In addition, these drugs can also lower potassium and magnesium contractions, conditions sometimes associated with abnormal electrocardiograms.


     Side effects include light-headedness, an increase in blood sugar and muscle cramping. Avoid excessive exercise with clients taking Metolazone (Diulo and Zaroxolyn) since they can be more active than usual while angina pain is masked.  Expect earlier fatigue.


     Diuretics are generally not considered a good means for controlling high blood pressure for those who wish to exercise.  Generally, there is no change in heartrate response with diuretics.  However, the cardiac output may increase or decrease as a result of the effect the drugs have on the stroke volume.  By reducing the amount of blood volume in the system, blood pressure will also be reduced.  This does not affect the exercise heartrate response. 

     Clients who overuse diuretics to keep their bodies looking lean may experience hypovolemia, which is a decrease in blood volume.  Indications of hypovolemia include nausea, fainting, lightheadedness, and hypotension.


    Use of diuretics can cause dehydration and other medical complications.  Dehydration is caused by the excretion of water and electrolytes (including sodium) from the kidneys and a decrease in blood volume.  Clients using diuretics should be cautioned to drink water before, after, and during exercise.


     Diuretics include acetazolamide (Diamox), aldomet (Methyldopa), amiloride (Midamor), bumetanide (Bumex), chlorthalidone (Hygroton), clonodine (Catapres), ethacrynic acid (Edecrin), furosemide (Lasix), indapamide (Lozol), metolazone (Diulo, Zaroxolyn), spironolactone (Aldactone), and triamterene (Dyrenium).


     Xanthines, called Bronchodilators, are used for acute bronchial asthma relief, possibly prevent episodes of asthma, and occasionally improve chronic bronchitis and emphysema.  Theophylline, the active medicine, inhibits the enzyme phosphodiesterase, and increases cyclic AMP.  This causes relaxation of the muscles in the bronchial tubes and lung blood vessels, resulting in relief of bronchospasm, and improved lung circulation.


     Common side effects of bronchodilators are nervousness, insomnia, rapid heart rate, dizziness, and heart rhythm disturbances.


     They include aminophylline (Phyllocontin, Truphylline), dxphylline (Dilor, Lufyllin), oxtriphylline (Choledyl), and theophylline (Bronkodyl, Slo-Phyllin, Theolair).


     Muscle Relaxants, called Skeletal Muscle Relaxants, are used for relief of nervous tension and anxiety.  By enhancing the nerve transmitter gamma-aminobutyric acid (GABA), these drugs help to block higher brain centers and cause calming.


     Common side effects include dizziness, fainting, slurred speech and excessive sweating.

     They include baclofen (Lioresal), carisoprodol (Rela, Soma), chlorphenesin carbamate (Maolate), chlorzoxazone (Paraflex, Parafon Forte), dantrolene (Dantrium), diazepam (Valium), meprobamate (Equanil, Miltown), metaxalone (Skelaxin), methocarbamol (Robaxin), and orphenadrine (Norflex).


     Digitalis is a stimulant for the heart and is commonly prescribed for clients with congestive heart failure or heart disorders.  It is also used as a prevention of arrhythmia.  It increases calcium, which increases the force of the heart muscle contraction.  It delays electrical stimulation in the heart creating a more regular rhythm.


     Common side effects are a decreased resting heart rate but digitalis may increase or decrease heartrate response to activity.  Clients taking digitalis should have medical clearance before being allowed entry into a program.


     Deslanoside (Cedilanid-D), digitoxin (Crystodigin), and digoxin (Lanoxicaps, Lanoxin) are common heart disorder medications.


     Tranquilizers, Antidepressant and Antianxiety Drugs increase norepinephrine and seratonin (brain chemicals) that transmit nerve impulses.


     Common side effects include nervousness, insomnia, drowsiness, dizziness, fatigue, irregular heart rhythms, sweating, blurred vision, confusion, decreased appetite and weight loss.


     Tranquilizers and antidepressant drugs include including fluoxetine (Prozac), venlafaxine (Effexor), amitriptyline (Elavil, Endep), amoxapine (Asendin), clomipramine (Anafranil), desipramine (Norpramiin, Pertofrane), doxepin (Adapin, Sinequan), imipramine (Janimine, Tofranil), nortriptyline (Aventyl, Pamelor), protriptyline (Vivactil), trimipramine (Surmontil), maprotiline (Ludiomil), bupropion (Wellbutrin), fluvoxamine (Luvox), nefazodone (Serzone), paroxetine (Paxil), sertraline (Zoloft), and trazodone (Desyrel).


     Antianxiety Drugs (minor tranquilizers), create a calming effect by changing the brain chemicals dopamine, norepinephrine, and seratonin.  Common side effects include dizziness, fainting, rapid heart rate, drowsiness, lethargy and fatigue.


     Antianxiety drugs include buspirone (Buspar), chlormezanone (Trancopal), hydroxyzine (Atarax, Vistaril), lorazepam (Ativan), and meptobamate (Equanil, Miltown).


   Tranquilizers, antidepressants and antianxiety drugs may increase, decrease or not affect the heartrate response. If anxiety is reduced by tranquilizers, the resting heartrate will often be decreased. While antianxiety drugs decrease the heartrate, tranquilizers and antidepressants will usually increase the heartrate response. Some tranquilizers may also cause arrhythmia. Each of these types of drugs may also reduce blood pressure.


   Antihistamines are common in many cold medications and allergy products. They may have no effect on the heartrate response or increase it. Antihistamines may also increase blood pressure, cause fatigue, drowsiness, and dryness of the mouth and throat.


   Diet pills should be discouraged as a poor approach to weight loss. Diet pills with sympathomimetic activity (SA) can increase the heartrate response. Diet pills should be used only with a physician’s approval.


   Alcohol use should be discouraged by the practitioner. Exercise should be prohibited for anyone under the influence of alcohol. The effects of alcohol (uncoordination) will increase the possibility of injury during exercise. Alcohol can either increase or decrease the heartrate response.


   Caffeine, which is found in coffee, chocolate, and many soft drinks, may increase or have no affect on the heartrate response. Use of caffeine should be limited by clients. The heartrate response to caffeine is usually dose related.


     Nicotine use should be discouraged.  Smoking cessation programs often include the use of smoking deterrents (Habitrol, Nicoderm, Nicotrol, Prostep, Nicorette, etc) which also contain nicotine.


     Side effects of nicotine use (in cigarettes or smoking deterrents) are a rapid heart rate and increased sweating. Clients who smoke or use a smoking deterrent drug should use a lower target heartrate and a lower exercise intensity.  



Special Thanks To:

Douglas Mc Manus, MD

Martin Becker, Registered Pharmacist

Steve Ziebell, Registered Pharmacist

Janine M. Talty, D. O., MPH



This article is an excerpt from AQUATICS - The Complete Reference Guide for Aquatic Fitness Professionals by Ruth Sova.  The book is available and                  







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Ruth Sova, MS, an internationally known speaker, author and consultant, is founder of six different businesses including the Aquatic Therapy and Rehab Institute, the Aquatic Exercise Association, Living Right Magazine, America's Certification Trainers, Armchair Aerobics Inc, and the Fitness Firm.  A leader in the health and wellness industry, she also draws on her vast experience as an entrepreneur to teach others what it takes to assume the risk of business and enterprise.  Ruth is on the Wisconsin Governor's Council on Physical Fitness and the author of numerous articles and fifteen books on her specialties of aquatic wellness and business.  She is the recipient of the:

                                Governor's Entrepreneurial Award

                                Suomi College Entrepreneurial Award

                                IDEA Outstanding Business Person Award

                                AEA's Contribution to the Industry Award

                                CNCA's Merit Award

                                AAHPERD's Honor and Service Awards

                                AHA's Outstanding Fund Raising Award

                                Wisconsin State Assembly Commendation

                                Key to the City of Port Washington, WI

                                Commemorative First Presidential Sports Award - Aquatic Exercise                                                                  Sevier-McCahill Disability International Foundation Award

                                Sara’s City Workout Aquatic Instructor of the Year

                    John Williams, Jr. International Swimming Hall of Fame Adapted Aquatics Award