Question:
On Shivah Asar B’Tammuz, I understand that someone who is sick does not have to fast. But how sick does a person actually have to be to be exempt? Does it require being bedridden, or is a milder illness enough? I’m not bedridden, but I’m also not fully healthy. I’ve been dealing with a strong flu for the past few days—I feel weak, achy, and drained, and I’m mostly staying in bed, though I can get up if needed. I’m worried that fasting will make me feel much worse. Do I still have to fast on Shivah Asar B’Tammuz, or am I considered exempt?
Answer:
A person is exempt from fasting if he is considered clinically “ill” (choleh), meaning he feels weakness throughout his body or is confined to bed due to his condition. Even without danger, such a person should not fast. In some cases, even milder illness may qualify, especially if the fast would worsen the condition. Thus, in your situation, you would be considered a choleh (sick person) and are exempt from fasting. You should not fast, even if there is no danger, and you should not be stringent on yourself to do so.
Explanation:
The Sages did not obligate someone who is considered a choleh to fast on the Rabbinic fasts, including Shivah Asar B’Tammuz. The key question, however, is how to define this level of illness.
The general definition given by the Poskim is that a person is considered a choleh she’ein bo sakana (ill, though not in danger) if his condition causes weakness throughout the body or confines him to bed. In such a case, he is fully exempt from the fast, even if there is no concern of danger, and he should not be stringent to fast. However, the exact threshold is subject to some interpretation. While many sources describe illness as being bedridden or generally debilitated, others indicate that even a milder sickness may qualify, depending on the individual’s condition and how the fast affects him. If fasting would significantly worsen the illness, that itself may render the person exempt.
A similar consideration applies to a person who is very weak: if a doctor advises that fasting would be harmful, he is treated like a sick person and does not fast. Likewise, if one becomes unusually weak from fasting—beyond what is typical—some opinions consider him within the category of choleh. By contrast, someone who is merely in pain but not truly sick is generally required to fast, although some authorities allow leniency in cases of extreme discomfort.
In summary, the exemption is not limited strictly to someone bedridden, but rather applies to anyone whose illness meaningfully weakens his body or would be adversely affected by fasting. When in doubt, especially in borderline cases, one should consult a competent Rav and, if relevant, a medical professional.
In your case, since you are experiencing systemic symptoms (weakness, fatigue, body aches) and are largely confined to resting—even if you are technically able to get up—this fits the classic definition of a choleh. The defining factor is not absolute immobility, but rather that the illness weakens the entire body and interferes with normal functioning.
Sources:
Definition of choleh she’ein bo sakana regarding fast days and Criteria of “weakness of the entire body” or being bedridden: Chayeh Adam 133:6; M”B 550:4; Implication of Aruch Hashulchan 550:7 and Hagahos Rav Akiva Eiger 559:9; See however Aruch Hashulchan 554:7 that this applies even if he is not bedridden; See Nitei Gavriel 5:4 in name of Maharam Bent 550 that even if he is slightly ill one may be lenient
The rule that Rabbinic fasts were not instituted for the sick: Michaber 554:6 regarding Tishe Be’av; Rama 686:2 [regarding Taanis Esther]; Chayeh Adam 133:6; M”B 550:4; Kaf Hachaim 550:7
The prohibition against being stringent to fast when exempt due to illness: M”B 550:4; Kaf Hachaim 550:7
The role of a doctor’s instruction in exempting a weak person: Kaf Hachaim 550:6 in name of Ruach Chaim 550:1