The Effect of Fasting on the Pulse Spectrum

Yi Chang Su

Abstract: Nutrition is the major source of bioenergy. The present study investigated the physiological response to fasting by analyzing the effect of fasting on the pulse spectrum of the radial artery. Sixteen subjects were allowed to take only mineral water for 24 hours, and the pulse was measured at intervals during fasting and after eating resumed. Data were analyzed using one-way analysis of variance (ANOVA) with Scheffe’s test for pairwise comparisons. The results indicate the second harmonic of the radial pulse increased and the sixth harmonic decreased significantly after 24 hours of fasting. The proportions of the second harmonic then decreased significantly and those of the sixth harmonic increased significantly 12 hours after eating resumed. These findings suggest that a rhythm exists in physiological changes and the distribution of bioenergy, which ensures that the overall heart load will remain unchanged during the fasting and re-feeding periods, maintaining a stable overall balance in body function.

In traditional Chinese medicine (TCM), the nutritive qi (ying qi) is considered the major source of energy for the body. Consequently, whether a person is “eating” or “fasting”, the use of energy in the body and its distribution will both be affected. In addition, fasting is known to affect certain hormonal secretions (such as GH, TSH, LH). The effects of fasting on surgery have also been explored. Chang reported that fasting has a clear effect on pulse, but was unfortunately unable to understand the nature of the effect owing to deficiencies in equipment (Chang, 1988). Wang observed that feeding caused changes in the pulse spectrum, discovering that the second and fourth harmonics showed clear increases with feeding while the fifth, sixth, seventh, eighth and ninth harmonics were lowered (Wang et al., 1996).

In the “Nei Ching”, a classic of Chinese medicine, the treatise “Lingshu-Wuwei” states that “after half a day of fasting, the qi weakens, and after a full day of fasting, it is very low “(Wang, 1975a). The “Lingshu-Pingren Jueku” chapter states that “If a normal person does not eat or drink for seven days, his essential qi and fluids from grain and water (food) will be exhausted” (Wang, 1975b). And in the “Suwen-Wuzangbie” treatise, it says, “The foods that enter the body are stored in the stomach, in order to nourish the qi of the five viscera. The “qi opening” (qi kou) is also called the taiyin, and is the source of nourishment of the five viscera. Changes in the level of nourishment can be seen in the “qi opening” (qi kou)” (Wang, 1975c). The “Suwen-Jingmai Bielun” also mentions a similar point, “Nourishment enters the stomach and is transmitted to the lungs, and therefrom to the hundred pulses, which send energy to the skin and hair. The hair and pulses are thus fed and can perform their function in the body. The body’s spirit is in the four organs.” When the qi is balanced, “the amount of qi decides life or death for the individual” (Wang, 1975d). Chinese medicine theory describes that after eating the nutrition in food becomes “defense qi” (wei qi), which comprises the main matter of the body in the vessels. Thus, fasting results in a reduction of wei qi. Fasting for half a day to a day is considered to generate evident changes in the qi, while fasting for seven days may result in death. The reduction in wei qi is evident in the “qi opening” (qi kou), and can also be observed in the radial pulse. Observations of these changes provide information about bodily functions.

The above evidence shows that both feeding and fasting have an effect on internal physiological functions and cause certain physiological reactions in pulse harmonics. The current study investigates the effect of fasting on changes in the harmonic spectrum of the radial pulse, and explores the distribution of energy in related pulse tracks and reaction pathways and pulses.

Materials and Method

A. Sampling Method

Sixteen healthy adults (eleven males, five females) who were students at a college of traditional Chinese medicine participated in this study. The age of the subjects ranged from 20 to 25 (mean [+ or -] SD age 23 [+ or -] 1.2).

The criteria for “healthy adults” were as follows: (1) self-reported feeling of good health, (2) generalized blood study within normal limits, and (3) no abnormalities found on a physical examination by a physician.

B. Study Design

This study used a one-group comparison design. The pressure pulse spectrum of subjects was received during the fasting and re-feeding periods. Observation of the pulse spectrum was performed at eight discrete time periods. Baseline values for the beginning of the fasting period were measured two hours after the last meal (point X). Observations were taken six hours, twelve hours, and twenty-four hours after point X (labeled as point A, point B and point C, respectively). Re-feeding was begun after point C, and observations were then also taken two hours, six hours, twelve hours and twenty-four hours after commencement of re-feeding (labeled as points D, E, F, and G respectively).

C. Fasting

During the fasting period, subjects were not allowed to eat any solid or liquid food. And were only allowed to ingest mineral water supplied from the same lot. Re-feeding was administered to all subjects using the same composition.

D. Instruments

This study used the pulse spectrum analyzer designed by Professor Wei-kung Wang, to measure changes in pulse spectrum harmonics. This instrument measures the pulse signal using a pressure transducer (SL-200GL Kyowa Electronics Instruments Co. Ltd. Japan). The output of the pressure transducer was connected to an IBM PC via an A/D converter with a sampling rate of 430 data point/sec. The pulse spectrum was analyzed with Fourier transform software using T (period) = 1 pulse (Wang et al., 1989c; Wang and Wang Lin, 1992a; Young et al., 1989b).

E. Experimental Procedure

All of the volunteers were asked not to take any medications during the three days prior to the experiment. A half-hour rest was routinely required before testing. Room temperature was maintained between 24~26 [degrees] C. Each subject was asked to lie down and relax with eyes open for five minutes. The pulse pressure in the right hand radial artery was then recorded using the pressure transducer, which was fixed to the skin by scotch tape and an adjustable belt with a small button to give suitable pressure for measurement by the transducer.

F. Analysis of Data

To be included in further analysis the data had to show heartbeat stability; i.e., for at least six continuous waveforms the wavelength standard deviation (heart rate) would not exceed 5%.

For data that met this criteria was calculated as follows: a percentage difference of harmonic proportions (%D-HP) between point X and point A to G. Variation was defined as the percentage difference in the Nth harmonic value [%D-HP (Ti)]= {[Cn (Ti)- Cn (T0)]/Cn (TO)} x 100%

%D-HP (Ti): difference of harmonic proportion

Cn: nth harmonic proportion = (An/Ao) x 100% for n = 1 to 10; for n=0, we define C0=A0

Ti: observation point after commencement of fast (A, B, C, D, E, F or G)

TO: X point (2 hours after last meal) set as the beginning of the fast period

An: amplitude of the nth harmonic of the pulse spectrum

A0: DC component of the pulse spectrum

G. Statistical Analysis

The statistical procedures used to analyze the pulse spectrum measurements were as follows:

(1) In order to control differences in individual volunteers at time X, the differences in each time segment (A, B, C, D, E, F, G and X) were converted to percentages as described above.

(2) Statistical analysis was performed by analysis of variance (ANOVA) with subsequent analysis of significance by Scheffe’s test.

Results

The pulse spectra for sixteen subjects were analyzed for the 24 hours of fasting and for the subsequent 24-hour re-feeding period. The average values and standard deviations of the results are shown in Table 1. CO represents blood pressure values, C1 represents the first heartbeat harmonic, and C2-C10 represent the second through the tenth heartbeat harmonics.

Table 1. Average Values and Standard Deviations for Subjects’ Harmonics

Time X A B

C0 3382.9 [+ or -] 37 3421.8 [+ or -] 38 3390.3 [+ or -] 48

C1 2475.2 [+ or -] 37 2467.7 [+ or -] 21 2583.2 [+ or -] 33

C2 1442.8 [+ or -] 41 1533.8 [+ or -] 39 1599.9 [+ or -] 33

C3 1541.2 [+ or -] 26 1569.5 [+ or -] 27 1527.5 [+ or -] 26

C4 860.7 [+ or -] 17 854.1 [+ or -] 12 825.2 [+ or -] 13

C5 686.5 [+ or -] 14 613.8 [+ or -] 13 664.9 [+ or -] 96

C6 478.6 [+ or -] 13 425.3 [+ or -] 13 426.5 [+ or -] 10

C7 245.7 [+ or -] 94 220.2 [+ or -] 77 206.5 [+ or -] 65

C8 131.6 [+ or -] 50 131.8 [+ or -] 40 120.5 [+ or -] 38

C9 114.5 [+ or -] 40 104.9 [+ or -] 40 112.0 [+ or -] 47

C10 86.4 [+ or -] 38 86.2 [+ or -] 31 73.8 [+ or -] 34

Time C D E

C0 3255.3 [+ or -] 22 3253.0 [+ or -] 31 3148.0 [+ or -] 33

C1 2367.9 [+ or -] 35 2222.9 [+ or -] 27 2329.8 [+ or -] 33

C2 2078.5 [+ or -] 57 1911.9 [+ or -] 53 1781.5 [+ or -] 50

C3 1357.8 [+ or -] 25 1581.9 [+ or -] 31 1577.1 [+ or -] 23

C4 833.5 [+ or -] 13 802.5 [+ or -] 17 848.7 [+ or -] 15

C5 545.6 [+ or -] 15 569.0 [+ or -] 97 644.2 [+ or -] 11

C6 283.0 [+ or -] 10 347.6 [+ or -] 13 393.5 [+ or -] 14

C7 158.2 [+ or -] 71 192.6 [+ or -] 83 212.2 [+ or -] 11

C8 120.8 [+ or -] 53 134.6 [+ or -] 56 140.6 [+ or -] 64

C9 84.9 [+ or -] 29 103.8 [+ or -] 39 97.8 [+ or -] 27

C10 70.0 [+ or -] 30 76.8 [+ or -] 34 76.6 [+ or -] 29

Time F G

C0 3432.0 [+ or -] 43 3247.0 [+ or -] 33

C1 2550.5 [+ or -] 30 2416.0 [+ or -] 21

C2 1390.1 [+ or -] 21 1643.0 [+ or -] 47

C3 1512.4 [+ or -] 29 1638.4 [+ or -] 23

C4 813.4 [+ or -] 16 876.0 [+ or -] 18

C5 705.2 [+ or -] 11 604.4 [+ or -] 10

C6 517.7 [+ or -] 11 379.5 [+ or -] 13

C7 249.6 [+ or -] 10 202.2 [+ or -] 98

C8 143.7 [+ or -] 43 125.7 [+ or -] 58

C9 105.7 [+ or -] 34 91.2 [+ or -] 42

C10 91.6 [+ or -] 22 78.2 [+ or -] 52

Time: X: 2 hours after last meal, A:6 hours into fast, B: 12 hours into fast, C: 24 hours into fast, D:2 hours into re-feeding, E: 6 hours into re-feeding, F: 12 hours into re-feeding, G:24 hours into re-feeding.

Average values for CO, which represent the DC component of pulse spectrum during the fasting and re-feeding periods, are shown in Figure 1. ANOVA analysis and Scheffe’s test found no significant differences for the CO averages for each period.

[Figure 1 ILLUSTRATION OMITTED]

The normalized amplitude and difference in harmonic proportion for each pulse were calculated. The differences in harmonic proportions for C0 to C10 at fasting six hours, twelve hours and twenty-four hours, as well as re-feeding two hour points, were converted to percentages as shown in Figure 2. The figure shows that differences in the harmonic proportion for the second harmonic increased as the fasting time increased, while differences in the harmonic proportion of the sixth harmonic showed a decreasing trend. Differences in the harmonic proportion of harmonics three, five, and ten showed their lowest values at 24 hours fasting; differences in harmonic proportion for harmonics four and eight showed only slight variations among the different periods. Two hours into the re-feeding period, the differences in the harmonic proportion for first and second harmonics showed a decreasing trend, while those for the third, fifth, sixth, seventh, eighth, ninth and tenth showed an increasing trend. Differences in the harmonic proportion for the fourth harmonic showed no significant variation during the period of observation.

[Figure 2 ILLUSTRATION OMITTED]

The differences in the harmonic proportion for C0 to C10 at measurement points two, six, twelve and twenty-four hours into the re-feeding period are shown in Figure 3. The data shown in the figure reveals that at two and six hours into re-feeding, differences in the harmonic proportion in the first and fourth harmonic showed an upward trend, while those for the fifth, sixth, seventh and tenth showed a continued increasing trend. The second and third harmonics showed no significant change during these periods. Twelve hours into the re-feeding period, differences in harmonic proportion of the second, third and fourth harmonics showed a decreasing trend, while those for the fifth, sixth, and seventh harmonics, as well as the tenth harmonic, showed a clearly increasing trend. On the other hand, at the measurement point twenty-four hours into re-feeding, the differences in the harmonic proportion for the second, third and fourth harmonics all showed increasing trends, while those for the fifth, sixth, seventh and tenth harmonics showed clear decreasing trends. Differences in the harmonic proportion for the eighth harmonic reached a maximum at the six hour point in the re-feeding period while the harmonic proportion for the ninth harmonic showed an upward tendency at two hours into re-feeding, and then began to decrease again.

[Figure 3 ILLUSTRATION OMITTED]

In Figure 4, the ANOVA and Scheffe’s test revealed that differences in the harmonic proportion for the second harmonic values measured during the fasting period (from six hours into fasting (A) to twenty-four hours into fasting (C)) revealed a statistically significant increasing trend (p [is less than] 0.01). Differences in the harmonic proportion for the second harmonic values measured during the re-feeding period (from two hours into fasting (D) to twelve hours into fasting (F)) revealed a statistically significant decreasing trend (p [is less than] 0.01). In Figure 5, differences in the harmonic proportion for the sixth harmonic at points twelve hours into fasting (B) and twenty-four hours into fasting (C) were characterized by a clear decreasing trend, which was statistically significant (p [is less than] 0.05). Differences in the harmonic proportion for the sixth harmonic at points twenty-four hours into fasting (C), two hours into re-feeding (D) and twelve hours into fasting (F) were characterized by a clear increasing trend, which was statistically significant (p [is less than] 0.05).

[Figures 4-5 ILLUSTRATION OMITTED]

Discussion

Chinese medicine theory describes the human body as a dynamically balanced system, with the five viscera responsible for harmonizing the physiology of the body, including energy distribution and use. This theory implies when the quantity of energy sources entering the body is reduced, the related distribution pathways or reaction pathway energy distribution and pulse rhythm must change as well. This effect has seldom been mentioned in classic texts or in modern research studies, therefore, the present study attempted to observe the harmonics of the pulse during fasting and re-feeding.

The present study uses a pulse harmonic spectrum analyzer developed by Professor Wei-kung Wang of Academia Sinica. The advantages of this instrument include its ability to convert data through Fourier analysis (Stanley et al., 1984) to harmonic spectra. Changes in the harmonic spectra can be used to investigate changes in physiological functions and related organs of the human body. Wang et al. (1987) reported a basis for physiological diagnosis based on pulse harmonic theory and the dynamics of blood flow. In addition, several previous studies showed that the resonant conditions of blood distribution to the liver, spleen, kidneys and other organs were related to the Fourier components of the pulse (Wang et al., 1989a; Wang and Wang Lin, 1991; Yu et al., 1994). Each organ has a particular resonance frequency, and the blood waves passing through the organ change in spectrum. The magnitude of the DC value of the blood pressure waves (C0) is the total load on the heart for one cycle. Consequently, the larger this value, the greater the load on the heart (Wang Lin et al., 1992). According to previous clinical studies and ligation studies in mice, the first harmonic is related to the liver, the second to the kidneys, the third to the spleen and the fourth to the lung (Wang et al., 1989b, 1991, 1992b; Young et al., 1989a, 1992).

According to the results of the analysis of pulse spectra during fasting and re-feeding in the present study, the DC value of C0, which represents blood pressure, was not significantly altered during the 24 hour fasting period and the 24 hour re-feeding period. The second harmonic, representing the kidney, showed an upward tendency during the 24 hour fasting period and fell to its lowest point during the first 12 hours of re-feeding, both trends being statistically significant. The sixth harmonic, which represents the gallbladder qi, behaved in an opposite manner to that of the second harmonic. During the 24 hours fasting period, it exhibited a significantly decreasing trend, rose with a significantly increasing trend to its maximum value during the first 12 hours of re-feeding. These trend analyses indicate that during the fasting period, the physiological changes may relate to the ingestion of food and drink and the distribution in the body has a clear rhythm. The significant changes during each segment of time which represent changes in the qi of the kidneys at C2 and the gallbladder qi at C6, showed opposite trends which ensured that there was no net change in the load to the heart during the 24-hour fasting period and the subsequent 24-hour re-feeding period. This compensation maintains the overall balance and stability of the organism. These findings indicate that the human qi is made up of two components: original qi (yuan qi, also called true qi, zhen qi) and nutritive qi. When nutritive qi is reduced, the original qi rises to compensate for the body’s needs. Nutritive qi is centered in the spleen and stomach, and original qi is widely thought to reside in the kidneys. The function of gallbladder qi is associated with the transportation of kidney qi. During fasting, the spleen and stomach qi is reduced, therefore, kidney qi must increase to compensate for this reduction; otherwise a clear change in gallbladder qi will happen. This hypothesis is worthy of further investigation with fasting patients in clinics, such as patients with pancreatitis or post-operative patients, and may provide further understanding of the physiological effects of fasting.

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Yi Chang Su, Ke Feng Huang, Yu Hsin Chang, Tsai Chung Li, Wei San Huang and Jaung Geng Lin(*)

Basic Chinese Medicine Laboratory, Institute of Chinese Medical Science, China Medical College, 91, Hsueh-Shi Rd., Taichung, Taiwan

(*)Corresponding author

(Accepted for publication May 4, 2000)

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