The effects of spaceflight microgravity on the musculoskeletal system of humans and animals, with an emphasis on exercise as a countermeasure: a systematic scoping review.

The purpose of this systematic review is twofold: 1) to identify, evaluate, and synthesize the heretofore disparate scientific literatures regarding the effects of direct exposure to microgravity on the musculoskeletal system, taking into account for the first time both bone and muscle systems of both humans and animals; and 2) to investigate the efficacy and limitations of exercise countermeasures on the musculoskeletal system under microgravity in humans.The Framework for Scoping Studies (Arksey and O'Malley 2005) and the Cochrane Handbook for Systematic Reviews of Interventions (Higgins JPT 2011) were used to guide this review. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist was utilized in obtaining the combined results (Moher, Liberati et al. 2009). Data sources, PubMed, Embase, Scopus, and Web of Science were searched for published articles through October 2019 using the Mesh terms of microgravity, musculoskeletal system, and exercise countermeasures. A total of 84 references were selected, including 40 animal studies and 44 studies with human participants. The heterogeneity in the study designs, methodologies, and outcomes deemed this review unsuitable for a meta-analysis. Thus, we present a narrative synthesis of the results for the key domains under five categories: 1) Skeletal muscle responses to microgravity in humans 2) Skeletal muscle responses to microgravity in animals 3) Adaptation of the skeletal system to microgravity in humans 4) Adaptation of the skeletal system to microgravity in animals 5) Effectiveness of exercise countermeasures on the human musculoskeletal system in microgravity. Existing studies have produced only limited data on the combined effects on bone and muscle of human spaceflight, despite the likelihood that the effects on these two systems are complicated due to the components of the musculoskeletal system being anatomically and functionally interconnected. Bone is directly affected by muscle atrophy as well as by changes in muscle strength, notably at muscle attachments. Given this interplay, the most effective exercise countermeasure is likely to be robust, individualized, resistive exercise, primarily targeting muscle mass and strength.

The threshold for myocardial ischemia varies in patients with coronary artery disease depending on the exercise protocol.

It is generally accepted that angina pectoris and, presumably, myocardial ischemia occur at a fixed heart rate-systolic blood pressure product in a given patient. This concept of a fixed threshold has recently been challenged. To evaluate the effects of varying exercise intensity on the ischemic threshold, 33 patients with coronary artery disease and provokable myocardial ischemia, documented by thallium-201 myocardial perfusion imaging, underwent two exercise tests 2 to 7 days apart. A symptom-limited incremental treadmill exercise test was followed by a 20 min submaximal treadmill test at an intensity approximating 70% of the peak heart rate attained during the incremental test. During the incremental exercise test, angina pectoris developed in 16 patients and 17 patients were asymptomatic. At least 0.1 mV of ST segment depression developed in all subjects during the incremental exercise test at a mean exercise duration of 5.3 +/- 2.6 min, a rate-pressure product of 19,130 +/- 5,735 and oxygen uptake of 19.6 +/- 7.0 ml/kg per min. During the submaximal exercise test, 28 (85%) of the 33 patients had significant ST segment depression. Of these patients, 24 (86%) were asymptomatic, including 10 patients who had previously reported anginal symptoms during the incremental test. The average time to onset of 0.1 mV ST segment depression during the submaximal test was 8.1 +/- 4.5 min. These changes occurred at a rate-pressure product of 15,250 +/- 3,705 and an oxygen uptake of 14.3 +/- 5.9 ml/kg per min, and were significantly (p less than 0.001) lower than values observed during the graded exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of intravenous theophylline on exercise-induced myocardial ischemia. I. Impact on the ischemic threshold.

OBJECTIVES: Theophylline has been shown to delay the onset of myocardial ischemia and to prolong exercise duration. The present study was done to evaluate the mechanisms and actions of intravenous theophylline on the onset of ischemia and exercise duration. BACKGROUND: The ischemic threshold may be altered by the differential coronary vasodilation induced by endogenous adenosine. Theophylline is a competitive receptor antagonist of adenosine and may have a potential as an anti-ischemic medication. METHODS: A double-blind, placebo-controlled crossover trial using an infusion of intravenous theophylline (8.0 +/- 2.0 mg/liter) or placebo before exercise in 12 patients was done. Oxygen uptake, heart rate, blood pressure and heart rate-blood pressure product were determined at the onset of > or = 0.1-mV ST segment depression and angina pectoris, as well as at peak exercise. The extent of myocardial ischemia was evaluated by electrocardiographic criteria and quantitation of thallium-201 images at peak exercise. RESULTS: When compared with placebo, theophylline significantly delayed time to the onset of exercise-induced ischemia. Ischemia occurred at a higher heart rate-blood pressure product and oxygen uptake. Exercise duration was prolonged but was not associated with greater ischemia, as determined by oxygen uptake, ST segment depression, angina pectoris and size of thallium-201 defect. CONCLUSIONS: It is concluded that theophylline favorably alters myocardial ischemia not only by delaying its onset but also by enabling it to occur at a higher threshold without causing deleterious effects during exercise. The mechanism for the increased ischemic threshold may be through the inhibition of adenosine and the coronary steal phenomenon.

Effects of intravenous theophylline on exercise-induced myocardial ischemia: II. A concentration-dependent phenomenon.

OBJECTIVES: The effects of varying concentrations of theophylline on exercise-induced myocardial ischemia were evaluated in patients with stable coronary artery disease. BACKGROUND: Theophylline is a competitive antagonist of adenosine and may have potential as an anti-ischemic medication. It is not known whether these effects on myocardial ischemia are concentration dependent. METHODS: In a double-blind, randomized, crossover manner, 11 patients received, at 1-week intervals, placebo and each of three theophylline doses by intravenous infusion for 45 min. Graded exercise testing was performed before randomization and immediately after each infusion. Concurrent anti-ischemic medications were withheld for 24 h before each exercise test. Serum theophylline concentrations achieved were 3.9 +/- 1.0 mg/liter (low), 8.2 +/- 1.8 mg/liter (medium) and 13.2 +/- 2.3 mg/liter (high). RESULTS: Compared with placebo, none of the three theophylline infusions produced a significant alteration in rest heart rate, blood pressure, mean frequency or severity of ventricular ectopic activity or noncardiac symptoms. The time to onset of ischemia was progressively increased, with medium and high concentrations achieving statistical significance. Similar patterns were observed for oxygen uptake and the heart rate-systolic blood pressure product at the onset of ischemia. Total exercise duration was significantly prolonged with the medium and high concentrations. CONCLUSIONS: It is concluded that administration of varying doses of theophylline before exercise produces a clinically significant and concentration-dependent improvement in the indicators of myocardial ischemia in patients with chronic stable coronary artery disease.

Effect of dipyridamole therapy on myocardial ischemia in patients with stable angina pectoris receiving concurrent anti-ischemic therapy.

The effects of oral dipyridamole on exercise performance and anginal symptoms were evaluated in 15 men with stable angina pectoris. In a double-blind, randomized, crossover design, patients received 75 mg of dipyridamole or placebo every 8 hours for 2 weeks in addition to their previously prescribed cardiac medications. Graded exercise tolerance testing was performed twice before randomization, at the end of each treatment period, and after single-blind placebo washout. When compared with baseline tests, the time to onset of 0.1 mV ST-segment depression was similar between dipyridamole and placebo treatments (316 +/- 89 vs 345 +/- 102 seconds, respectively, p = not significant). No significant differences existed between treatments in the peak systolic blood pressure-heart rate product or in the duration of exercise. Angina pectoris occurred during all 3 baseline exercise tests in 7 of the 15 subjects; the time to onset of angina was unchanged by either treatment. Analysis of symptom diaries conducted in 13 patients revealed no significant alteration in reported anginal symptoms during dipyridamole treatment compared with placebo treatment (0.6 +/- 0.9 vs 0.3 +/- 0.4 episodes per week). Ambulatory electrocardiographic monitoring in 12 patients revealed few episodes of ischemia during daily activities with no alteration in frequency of episodes during treatment periods. Plasma concentrations of dipyridamole did not correspond with the outcomes of exercise testing. It is concluded that chronic oral dipyridamole therapy given in its usual clinical dose does not adversely affect exercise performance, daily anginal episodes or ambulatory ischemia in patients receiving concurrent anti-ischemic medication.

Comparison of chest pain, electrocardiographic changes and thallium-201 scintigraphy during varying exercise intensities in men with stable angina pectoris.

This study was performed to evaluate the presence of angina pectoris, electrocardiographic changes and reversible thallium-201 defects resulting from 2 different levels of exercise in 19 patients with known coronary artery disease and evidence of exercise-induced ischemia. The exercise protocols consisted of a symptom-limited incremental exercise test (Bruce protocol) followed within 3 to 14 days by a submaximal, steady-state exercise test performed at 70% of the maximal heart rate achieved during the Bruce protocol. The presence and time of onset of angina and electrocardiographic changes (greater than or equal to 0.1 mV ST-segment depression) as well as oxygen uptake, exercise duration and pressure-rate product were recorded. Thallium-201 (2.5 to 3.0 mCi) was injected during the last minute of exercise during both protocols, and the images were analyzed using both computer-assisted quantitation and visual interpretations. Incremental exercise resulted in anginal symptoms in 84% of patients, and electrocardiographic changes and reversible thallium-201 defects in all patients. In contrast, submaximal exercise produced anginal symptoms in only 26% (p less than 0.01) and electrocardiographic changes in only 47% (p less than 0.05), but resulted in thallium-201 defects in 89% of patients (p = not significant). The locations of the thallium-201 defects, when present, were not different between the 2 exercise protocols. These findings confirm the sequence of the ischemic cascade using 2 levels of exercise and demonstrate that the cascade theory is applicable during varying ischemic intensities in the same patient.

Plasma beta-endorphin levels in silent myocardial ischemia induced by exercise.

Although silent myocardial ischemia is a well recognized phenomenon, the reasons for the lack of symptoms in patients with coronary artery disease (CAD) is unclear. Because the endogenous opioid beta-endorphin has been related to pain modulation, plasma beta-endorphin levels were studied before, during and after exercise-induced ischemia in symptomatic and asymptomatic men. Because beta-endorphin responses have been closely linked to adrenocorticotropic hormone (ACTH) and cortisol responses, these hormones also were measured. Nine symptomatic and 12 asymptomatic patients with a high probability (at least 95%) of CAD and 8 apparently healthy men completed a Bruce protocol treadmill test. Blood samples were drawn before, during and 10 minutes after exercise. During exercise the measured hormones showed no significant increases from basal levels. However, plasma beta-endorphin, ACTH and cortisol levels were significantly elevated (p less than or equal to 0.01) 10 minutes after exercise in all 3 groups. There was no significant difference in plasma beta-endorphin levels during or after exercise between the symptomatic and asymptomatic patients with CAD. Thus, differences in circulating levels of beta-endorphin, ACTH and cortisol are not associated with the presence or absence of pain during exercise-induced myocardial ischemia.

Comparison of dobutamine and exercise using technetium-99m sestamibi imaging for the evaluation of coronary artery disease.

Studies using dobutamine thallium-201 myocardial perfusion imaging have suggested a high sensitivity and specificity for the detection of coronary artery disease. However, few data are available comparing dobutamine with exercise stress for the detection and localization of perfusion defects. This study compared the effects of dobutamine and exercise stress using technetium-99m sestamibi single-photon emission computed tomographic imaging in the same patients in a prospective crossover trial. Twenty-four patients with a high likelihood of coronary artery disease underwent tomographic myocardial imaging at rest, after symptom-limited treadmill exercise, and after intravenous dobutamine (maximum 30 micrograms/kg/min). Tomograms of the left ventricle were divided into 20 segments and were interpreted without knowledge of patient identity or stress protocol. Dobutamine was well tolerated by all patients. Segment-by-segment concordance between exercise and dobutamine images was highly significant (kappa = 0.56, p < 0.0001). Global first-order agreement (normal vs abnormal) between exercise and dobutamine studies was 96% (kappa = 0.65, p = 0.02); global second-order agreement (normal vs fixed vs ischemic defect) was 88% (kappa = 0.45, p = 0.02). Regional first- and second-order agreement were 96 and 93%, respectively (p < 0.001 for both). Twenty patients underwent coronary angiography. Comparisons between exercise and angiography and between dobutamine and angiography were similar for both global agreement (95 vs 100%, p = NS) and regional agreement (77 vs 72%, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of "Rose Questionnaire Angina" to exercise thallium scintigraphy: different findings in males and females.

Validation of the London School of Hygiene (Rose) Questionnaire with objective measures of myocardial ischemia is incomplete. Therefore, we compared the Rose Questionnaire with exercise thallium-201 myocardial scintigraphy in 147 male and 97 female patients with chest pain referred for clinical exercise testing. Of those with "Rose Questionnaire angina", 26% of the females and 73% of the males had positive thallium-201 scans. Negative results on both the Rose Questionnaire and thallium-201 scintigraphy were observed in 71% of the females and 47% of the males. The sensitivity of the Rose Questionnaire was similar in females (41%) and males (44%). The specificity was 77% in males, while in females it was significantly lower at 56%. The specificity values reflect the higher (p less than 0.05) prevalence of "false positive" Rose Questionnaire results in females (75%) compared with males (27%). In addition, males had a greater (p less than 0.05) number of "false negative" results (53%) than females (29%). The accuracy of the Rose Questionnaire for myocardial ischemia was 0.19 in females, 0.48 in males, and 0.29 overall when including both males and females. Our results indicate a generally poor relationship between Rose Questionnaire angina and thallium-201 scintigraphy, an objective measure of myocardial ischemia in patients with chest pain referred to clinical exercise testing. Further, there are gender-specific differences in this relationship between the questionnaire and exercise thallium-201 imaging.

Developing a competency-based preventive medicine curriculum for medical schools.

Trends in patient morbidity and mortality, cost-effectiveness, and national recommendations mandate that we practice more preventive medicine. To address this need, we set out to develop a comprehensive curriculum in preventive medicine for medical schools. We constructed a competency-based (i.e., performance-based) curriculum with specific educational objectives defined by outcomes. Subject areas were subdivided by life stages, and learning objectives were created separately for epidemiology, assessment, and intervention. We hope that adoption of such an educational blueprint by medical schools will measurably enhance the attitudes, knowledge, and skills necessary for the incorporation of preventive principles into all aspects of clinical medicine.

Cross-sectional relationship between diet and physical activity in two southeastern New England communities.

The hypothesis that health promotive diets associated with higher levels of habitual physical activity confound the relationship between regular physical activity and health has not been well explored in epidemiologic studies. We evaluated self-reported physical activity, Willett Food Frequency dietary data, sociodemographic and physiologic factors cross-sectionally for 2,004 household survey participants in two southeastern New England communities. We compared the dietary habits of sedentary participants (n = 964) to those of moderately active (n = 600) and very active (n = 440) participants after adjusting for age, gender, education, smoking status, year of survey, and total calories. Our results showed that moderately active and very active participants consumed more fiber, less total fat, and less saturated fat than sedentary participants (P < .01). They also consumed more vitamins (A, C, D, E), beta carotene, and calcium, (P < .01), and ate more fruits and vegetables (P < .001) than sedentary participants. We found these relationships in both New England communities studied. This association between regular physical activity and diet suggests that the relationship of habitual physical activity and chronic disease may be confounded by diet.

Cardiovascular changes in pregnancy evaluated by two-dimensional and Doppler echocardiography.

During pregnancy significant cardiovascular changes occur. To study these anatomic and physiologic changes we performed two-dimensional and Doppler echocardiography in 28 women during the third trimester (34.4 +/- 1.9 weeks) of pregnancy and then again after delivery (7.8 +/- 2.2 weeks). Fourteen nonpregnant age- and sex-matched subjects served as controls. Left ventricular diastolic and systolic dimensions were similar among pregnant, postpartum, and control subjects. Left atrial area as determined by two-dimensional echocardiography was significantly larger during pregnancy (16.7 +/- 4.0 cm2) compared with measurements postpartum (13.8 +/- 3.1 cm2) and with controls (15.5 +/- 3.5 cm2) (p less than 0.01). Doppler study showed that the ratio of early diastolic flow velocity to late diastolic flow velocity (E/A max) and E/A integral were lower among pregnant subjects (1.3 +/- 0.3, 2.0 +/- 0.5) compared with postpartum subjects (1.6 +/- 0.4, 2.5 +/- 1.5) and controls (1.9 +/- 0.5, 3.0 +/- 0.8) (p less than 0.05). Heart rate was higher among pregnant subjects (84 +/- 10 beats/min) compared with postpartum subjects (70 +/- 16) and controls (69 +/- 13) (p less than 0.05). In summary, in pregnant subjects during late third trimester left ventricular chamber dimensions were similar to these postpartum measurements in control subjects; however, the left atrium is dilated during pregnancy. Although there are significant alterations in Doppler-derived left ventricular diastolic parameters during the third trimester, increased heart rate and a dilated left atrium may explain these findings.

Physical activity, physical fitness, and coronary heart disease risk factors.

The relationships between physical activity, physical fitness, and coronary heart disease risk factors measured in a large community sample were evaluated. Self-reported physical activity using a single question, maximal oxygen consumption estimates derived from the Pawtucket Heart Health Step Test, blood pressure, nonfasting lipids, and body mass index were cross-sectionally evaluated in 381 men and 556 women. The correlation of estimated maximal oxygen consumption and self-reported physical activity was modest but statistically significant (r = 0.13 in men and r = 0.19 in women). Blood pressure, body mass index, and HDL cholesterol were correlated with physical fitness (r = 0.24-0.65) and correlated to self-reported physical activity (r = 0.09-0.14). Evaluation of coronary heart disease risk factors using both physical activity and physical fitness revealed a complex relationship that generally showed a stronger relationship with measures of physical fitness than with physical activity. This study suggests that simultaneous measurement of physical activity and physical fitness may be useful in epidemiologic studies of habitual physical activity and chronic disease.

Echocardiographic assessment of the cardiac anatomy in patients with multifocal atrial tachycardia: a comparison with atrial fibrillation.

Although multifocal atrial tachycardia (MAT) has been recognized since 1968, few data exist on its associated anatomic correlates. Using echocardiography, the authors describe the cardiac anatomy observed in hospitalized patients with MAT. Because MAT closely resembles atrial fibrillation (AF), these echocardiographic data are compared with those from an age- and sex-matched population with AF. There were 25 patients in each of the MAT and AF groups. Biatrial enlargement was present in both groups. However, the atrial enlargement was mild and significantly less in the MAT group. The MAT group had normal ventricular and aortic dimensions. Right ventricular dysfunction was rare in both groups. Moderate to severe global left ventricular dysfunction was present in 7 of 25 in the MAT group and in 9 of 25 in the AF group. Systolic wall-motion abnormalities were significantly less in the MAT group. Severe Doppler and structural abnormalities were not common in the MAT group. Based on these parameters, physiologic and not anatomic factors are probably more important in the genesis of MAT as compared with AF.

Circulatory effects of mental stress during exercise in coronary artery disease patients.

We examined the effects of mental stress during steady-state exercise on heart rate, blood pressure, pressure-rate product, and oxygen uptake in 10 coronary artery disease patients. Subjects walked at three mph with grade increases of 4% every two minutes until the target heart rate (60% peak heart rate from a previous symptom-limited exercise test) was reached. A computerized Stroop-Color-Word Test (mental stress) was added one minute after the subject reached steady-state exercise and lasted 11 +/- 4 minutes. When mental stress was added to steady-state exercise it significantly (p less than 0.01) increased the heart rate (101 +/- 15 to 108 +/- 19 beats per min), systolic (154 +/- 26 to 170 +/- 26 mmHg) and diastolic (86 +/- 10 to 92 +/- 13 mmHg) blood pressure, and pressure-rate product (158 +/- 42 to 179 +/- 48 x 10(-2)). This increase in the mean response during exercise and mental stress was not observed for oxygen uptake (17 +/- 6 to 18 +/- 5 ml/kg/min). The circulatory changes probably reflect increased sympathetic activity with both centrally mediated cardioacceleratory (and probably cardiac output) and vasoconstrictor effects during the combination of mental stress and steady-state exercise. The altered hemodynamics without concomitant changes in oxygen uptake has major implications concerning the safety of competitive exercise for people with coronary artery disease.

Coronary care unit requirements of patients with acute myocardial infarction treated with or without thrombolytic therapy: a pilot study.

OBJECTIVE: To determine if patients with acute myocardial infarction who receive thrombolytic therapy require more nursing care hours and a longer length of stay in the coronary care unit than those patients with acute myocardial infarction who do not receive thrombolytic therapy. DESIGN: Retrospective cohort study using the coronary care unit data base and patient classification records. SETTING: Northeastern university-affiliated, community-based, cardiovascular tertiary care center. PATIENTS: All patients admitted to the coronary care unit with a diagnosis of acute myocardial infarction were screened. Of these, 20 patients who also had a patient classification form completed were included in the study. Ten of these patients had received thrombolytic therapy and 10 had not. The patients were grouped according to treatment with a thrombolytic agent or conventional treatment. There was no significant difference in age between the groups (64 +/- 19 years and 67 +/- 15 years). OUTCOME MEASURES: Nursing care hours per patient per day and length of stay per patient in the coronary care unit. RESULTS: On days 1 and 2 of hospitalization, there were no significant differences in total nursing care hours provided per patient per day. On days 3 and 4, those patients who received thrombolytic therapy received fewer nursing care hours compared with those who did not (11.1 and 9.2 vs 13.8 and 12.7 hours per patient day, respectively; p < or = 0.05). Patients who were treated with thrombolytic therapy also had a significantly shorter coronary care unit stay (3.1 vs 4.0 days; p < or = 0.05). CONCLUSION: In this retrospective, observational pilot study, patients who received thrombolytic therapy for treatment of acute myocardial infarction had a significantly shorter coronary care unit stay and required significantly less nursing care on days 3 and 4.

Is aerobic dance an effective alternative to walk-jog exercise training?

In order to compare the physiological effects of an 8 week aerobic dance program to those of a walk-jog exercise training program, 60 male and female University employees ages 24-48 years were randomly assigned to an aerobic dance program (N = 22), a walk-jog program (N = 24), or a sedentary control group (N = 15). Subjects who had an exercise compliance rate less than or equal to 85% were dropped from the study, as were control subjects who had scheduling conflicts or illnesses precluding post-treatment testing. Thirty-five subjects completed the 8 week period with a compliance rate greater than or equal to 85%, leaving 14 in the aerobics group, 11 in the walk-jog group and 10 in the control group. Significant increases (p less than 0.001) in maximal oxygen uptake occurred in both the aerobics (+3.9 ml/kg-1/min-1) and walk-jog group (+3.4 ml/kg-1/min-1), while no significant change was observed in the control group. Peak heart rate decreased significantly (p less than 0.05) in the aerobics (-4 b/min-1) and walk-jog groups (-3 b/min-1 but was unchanged in the control group (-1 b/min-1) following the treatment period. Body weight, peak respiratory exchange ratio and peak minute ventilation remained the same in the aerobics, walk-jog and control groups throughout the treatment period. It is concluded that aerobic dance programs can result in similar improvements in aerobic power as a walk-jog program. Thus, an aerobic dance program is an effective alternative to a traditional walk-jog training regime.

A comparison of exercise performance on bicycle and rowing ergometers in female master recreational rowers.

Limited information exists on the response to maximal exercise testing in female masters level recreational rowers. This study examined cardiorespiratory and physiologic responses to progressive, incremental exercise using a variable resistance rowing ergometer and a cycle ergometer in six experienced female masters level rowers. Maximal oxygen uptake (VO2 max:33.8 +/- 7.3, 33.5 +/- 6.6 ml.kg-1.min-1) and minute ventilation (VEmax: 86.1 +/- 9.6 l.min-1, 88.7 +/- 13.8 l.min-1) were similar during both tests (rower vs cycle). Maximal heart rates were significantly higher on the cycle ergometer (177 +/- 9 beats/min-1) compared to the rowing ergometer (173 +/- 11 beats/min-1), while peak power on the rowing ergometer (175 +/- 22 watts) was lower than the cycle ergometer (187 +/- 41 watts). Blood lactate levels taken 1 minute following exercise were similar on the rowing ergometer (10.5 +/- 1.7 mM/l) and cycle ergometer (11.8 +/- 1.5 mM/l) and indicated maximal effort was achieved in all subjects. Ventilatory threshold levels were significantly different on the rower (2.0 +/- 0.16) versus the cycle ergometer (1.9 +/- 0.18) (p = 0.38). These data suggest that the cycle and rowing ergometers yield relatively similar results when testing maximal exercise performance in this population.

An assessment of pulmonary function testing and ventilatory kinematics by optoelectronic plethysmography.

New advances in computer processing and imaging have allowed the development of innovative techniques to assess lung function. A promising methodology is optoelectronic plethysmography (OEP). OEP evaluates ventilatory kinematics through the use of infrared imaging. Markers are placed, and images read on the chest, back and abdomen of subjects. Currently, this system is used mainly in research settings, but in the future may have broad applicability to patient populations such as very young children, patients with neuromuscular disease and patients who cannot be tested with classical spirometry testing. This paper presents the history and development of OEP, along with a summary of the OEP methodology, a discussion of research findings and results to date, as well as application and limitations.