Sudden death (SD), which unexpectedy occurs in the middle aged and the elderly, is a subject worth studying. Much about the cause of the demise remains shrouded in mystery from the standpoint of medicine and has a significantly great impact on the community.
We conducted a fact-finding survey of SD by gathering data on dead-on-arrival (DOA) cases stored by five general hospitals affiliated with the National Welfare Federation of Agricultural Cooperatives. Examined were 292 DOAs that were registered between January 1993 and December 1993 and autopsy findings of 45 cases obtained from one of the hospitals over the past eight years. The results are summed up as follows:
(1) The largest number of DOA cases was found in the age group of 70 to 79 years. About half of the total number was accounted for by people older than 70.
(2) Cardiovascular disease topped the list of causative and basal ailments that might have led to SD. Especially ischemic heart disease was evident in many cases.
(3) In many cases, death occurred during sleep or at rest.
(4) Cardiopulmonary resuscitation was performed according to rule on most of the victims, but the priamry resuscitation ratio came out at 26%.
From these observations, we concluded that for the prediction and prevention of SD and DOA it is necessary to work on measures to help prevent and cure ischemic heart disease.

During winter months, lotus growers have to harvest edible roots, waist-deep in the muddy fields. In addition to such an external factor as the cold, physical labor involved is so hard that a level of stress is considered high, especially on the cardiovascular system. In this study, we examined how hard the labor is on the cardiovascular system, based on the measurements of hemodynamic parameters taken in the fields while farmers were working. The subjects were comprised of a total of 18 lotus growers-11 men and 7 women-aged between 41 and 66 years (mean: 56.7 years old). During a week before the measurement was performed, a physical examination and an anaerobic threshold (AT) test were given. In the field, each examinee carried an ambulatory electrocardiograph with him or her and levels of blood Pressure (BP), heart rate (HR), and blood saturation-O₂ (SO₂) were measured. During work, the heart rate was elevated significantly, but did not exceed the evaluated maximum heart rate in every case. Immediately after the work, the HR returned to the level measured before the work began. No significant fluctuation was noted in BP, pressure-rate-products (PRP) and SO₂ even during the work. Any sign associated with ischemia was not observed on ECG, either. Soon after the work began, the blood pressure level tended to lower in women compared with that in men and the PRP did not rise in women so much as it did in the opposite sex. However, in two elderly subjects of over 60 years, arrhythmia was noted along with the elevation of blood pressure soon after the stop of the work. These results showed that harvesting lotus roots did not bring about marked changes in the hemodynamic parameters and that the caraiovascular load was slight. However, an adequate health control system should be worked out for the lotus growers of advanced age over 60.

There are many acquired and hereditary coronary risk factors, and the gender is known as a factor influencing the development of acute myocardial infarction (AMI). To evaluate the role of the gender in the occurrence of AMI, we compared patient backgrounds, their clinical manifestations, outcomes, and coronary angiographic findings between 390 male and 110 female AMI patients, who had been admitted to the coronary care unit (CCU) of the Tsuchiura Kyodo General Hospital and undergone coronary angiography on an emergency basis. The incidence of AMI was the highest in the age group of 60s for males, while for females in the age group of 70s. As coronary risk factors, smoking habit was more common in males, while hypertension, hyperlipidemia and diabetes meritus were more common in females. Coronary angiograms revealed no differences in the number of diseased vessels and location of infarction. Frequencies of urgent PTCA were also identical between the two groups. In clinical outcomes, elder females had poorer prognosis mainly due to a higher incidence of death caused by cardiac rupture. It has been reported that definite increase of AMI after menopause is attributable to disturbed lipid metabolism due to a reduced estrogen level. Our study showed that aged female AMI patients had poorer prognosis possibly due to associated multiple risk factors, mutiple organ disorders and delayed admission to hospital and higher risk of cardiac rupture. Therefore, in the treatment of aged female AMI patients, these tendencies must be taken into account.

This study was conducted to clarify the relationship between power estimated by blood lactate movement during intermittent running test (Maximal Anaerobic Running Test : MART), and velocity of middle distance running (V 800 m, V 1500 m) . The subjects were well-trained male middledistance runners (n=8) .
MART consisted of a variable number of 20 seconds runs on a treadmill with a 100 seconds recovery period between runs. The runs were performed ona a 4° incline. After 40 second recovery, earlobe blood samples were taken and blood lactate concentrations were analyzed. The first run was performed at 250 m/min. Velocity of the treadmill was increased by 25 m/min for each consecutive run until volitional exhaustion.
The power requirement associated with the absolute value of blood lactate (La) and relative value of peak blood lactate (PBLa) was determined from the La or %PBLa vs power curve by linear interpolation from the two consecutive La values which were above and below the desired value.
Results were summarized as follows:
(1) Maximal power (Pmax) for MART was correlated positively with V800m (r=0.880, P<0.01) and V1500m (r=0.948, p<0.001) .
(2) Power estimated at 40% value of PBLa (P40%La) correlated positively with V 1500 m (r=0.903, P<0.01), and at 60% value of PBLa (P60%La) was correlated positively with V800m (r=0.835, P<0.01) and 1500m (r=0.936, p<0.001) .
These results indicate that MART is a valid test for estimating middle distance running performance and P40%La, and P60%La are important indexes with 800-m and 1500-m running.